TIME PERFORMANCE
A Thesis Presented to the
Graduate Faculty of Health and Physical Education Eastern New Mexico University
In Partial Fulfillment of the Requirement for the Degree Master of Science
by
Tracie L. Edwards April 4, 2012
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Abstract of a Thesis
Presented to the
Graduate Faculty of Health and Physical Education Eastern New Mexico University
In Partial Fulfillment of the Requirements
for the Degree Master of Science
by
Tracie L. Edwards April 4, 2012
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One method is high-resistance (HR), which uses free weights or plate loaded machines. Another training protocol is high-velocity (HV), training which utilizes light loads and high repetitions along with plyometric exercises to increase speed and velocity. HV training is thought to improve overall sprint time performance whereas HR training will improve the initial acceleration phase of the 100 m sprint. The purpose of this study was to examine the effects of both HV and HR training programs on overall sprint time performance in female high school students. This study included 30 females from Roswell, New Mexico, ranging in age from 14 to 18 years. The participants, who were not familiar with strength training programs, were selected from the physical education classes at local high schools. For 8 weeks the students participated in either a HV (jumping, bounding, hopping, etc.) or HR (squat, hamstring curls, leg press, leg extension, etc.) training protocol. Both training groups improved the 100 m sprint time from the pre-test to the post-test over the training period, however, the results showed no significant difference between the two groups’ mean change scores on sprint times (F(1, 28) = 0.062, p > 0.05). Follow-up analysis showed the within-subjects results were statistically significant (F(1, 28) = 18.687, p < 0.001) indicating that the 8 weeks of training induced a significant change for individual sprint time performance regardless of protocol.
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started. I want to thank my husband for all of his support and allowing me to pursue my dream of getting a master’s degree. I also want to thank my family who lives so far away in South Texas for giving me the confidence to complete this study and to look forward to the future.
I want to thank Dr. Sarah Wall for all of her time and effort in guiding me through the tumultuous task of completing this study. She showed me the how to prepare for any future tasks that I may encounter along with encouraging me to finish what I started. I would also like to thank Dr. Mary Drabbs and Dr. Matt Martin for taking the time to be part of my thesis committee.
I would like to thank the faculty and staff members at Roswell High School; P. J. Garnett, Micah Trujillo, Monika Trujillo, and Michael Garcia; and Valley Christian Academy; Tim Fuller, and Zach Ryan; for letting me into their physical education classes and campuses. Lastly, I would like to thank the participants of the study who gave their time and effort to me during the study.
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Abstract iii
Acknowledgements v
List of Tables viii
Chapter I. Introduction 1 Problem Statement 3 Purpose Statement 3 Research Hypothesis 3 Operational Definitions 3 Limitations 4 Assumptions 4 Delimitations 4
Risk and Benefits 5
Significance of the Study 5
II. Review of Literature
Predicting Sprint Speed Based on Strength and Power 6
Effects of Specific Types of Training on Running Form 9
Strength Training For Adolescents 12
Training Method Effects on Sprint Time Performance 14
Summary 18 III. Methods Introduction 20 Participants 20 Setting 20 Research Design 21 Instruments 21 Validity of Study 21
vii Summary 25 IV. Results Introduction 26 Descriptive Statistics 26 Data Treatment 27 Statistical Analysis 27 Summary 28 V. Discussion Introduction 29 Hypothesis Findings 29
Pre- and Post-test Comparisons 31
Conclusions 33
Considerations for Future Research 33
References 36
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1 CHAPTER I
Introduction
An optimal level of strength, power, and force are necessary to maximize sprinting performance because sprinting requires a powerful start and a strong finish. Strength training when used as a form of physical conditioning can increase force, muscular strength and power. Methods such as high-resistance (HR) training have been used to increase velocity where sprint running and overall dynamic performance are involved (Delecluse et al., 1995). For example, HR training involves heavy loads with few repetitions and is designed to increase strength and power. A second popular method, termed high-velocity training (HV), involves light loads and high repetitions to increase speed and velocity. Other training methods using parachutes, sleds, weight belts and vests to improve explosiveness, quick acceleration, and first-step quickness have been studied to find the change in running
kinematics and to determine if an increase in power is obtained (Cronin, Hansen, Kawamori, & McNair, 2008). A variety of training programs have been studied to determine which method of training works best for improving sprint time and phase performance (Delecluse et al.). Resistance training in combination with speed and HV training methods have also been used to determine the effects of such training on different age groups; however, little research includes adolescent females as the particpants.
In 2007, Ignjatovic, Radovanovic, and Stankovic investigated how different resistance training programs affected muscular strength among children and male adolescents. Also, Blazevich and Jenkins (2002) studied male elite junior sprinters to determine the effects of high- and low-velocity resistance training on sprint running
and other sport-specific athletes to determine the ratio of strength and power needed to achieve maximal running speed and which training programs improve sprint performance (Faigenbaum et al., 2007). These studies provide insight for strength and conditioning coaches to improve not only the entire sprint performance for different age groups, but also different phases of the sprint.
The sprint has three phases: the initial acceleration, maximum running speed, and speed endurance (maintenance). In track and field, a sprinter may possess a good start but lack the ability to maintain maximum speed. The initial acceleration phase occurs between the start and 10 meters (m). The maximum running speed is achieved among untrained sprinters between 10 m and 60 m, but it may take an elite sprinter 80 m to reach top speed due to a higher endurance capacity (Delecluse et al., 1995). The endurance phase is the last 10 to 20 m of the sprint. In addition, training for the initial acceleration phase is different than training for maximum running speed (Delecluse et al.). Researchers have studied the impact of resistance training emphasizing the exact methods which improved the athlete’s time in each phase (Young, 2006). Some researchers suggest that the benefit of improved sprint time is gained from HR training (Delecluse et al.), but it has yet to be shown that a sprinter can improve his/her speed when the HR training is performed at higher movement velocities (Blazevich & Jenkins, 2002). In addition to resistance training, many athletes use other training components, such as speed and agility exercises to enhance the athletic performance, but Blazevich and Jenkins hypothesized that if athletes wish to improve their HV force production, resistance training exercises should be performed at high movement speeds.
Coaches and athletes are always looking for better training methods to improve an athlete’s performance, but to date few studies have shown that HR training improves overall sprint time performance. In addition, given the number of studies on training programs with junior and elite male athletes along with male adolescents, more information is needed for coaches of female students at the high school level.
Problem Statement
The problem was that little information existed about the effect of different training programs on sprint running performance in high school female students.
Purpose of the Study
The purpose of this study was to examine the effects of both high-velocity (HV) and high-resistance (HR) training programs on overall sprint time performance in female high school students.
Research Hypothesis
The hypothesis of this study was that HV training would result in a greater
improvement in sprint time when compared to HR training for high school female students. Operational Definitions
Power is the amount of work done per unit of time and is the product of force and velocity. P = Fv.
One repetition maximum (1RM) is the most amount of weight that a participant can lift for one repetition but not two.
High-resistance training (HR) uses heavy weights with movement performed at a safe speed and fewer repetitions to increase maximum strength.
High-velocity training (HV) uses the athlete’s body weight as the resistance where coordination and speed are emphasized during the movements. Exercises include jumps, skipping, ladder drills, bounding, and hopping.
Plyometric training is a technique used to develop explosive strength and power, and consists of a quick eccentric stretch followed by a powerful concentric contraction. Limitations
Limitations of this study include:
1. students may not be able to attend all of the training sessions;
2. extra training may be performed outside the required training sessions; 3. the study may be affected by injuries while training or dropout due to illness; 4. the students may not be motivated to perform the training or tests as specified by
the researcher;
5. the participants are part of a convenience sample from intact physical education classes.
Assumptions
Assumptions of the study are:
1. students will attend all training sessions;
2. extra training will not be performed outside the required sessions; 3. test participants will follow the testing protocols of the study;
4. test participants will give maximal effort during all training and testing sessions. Delimitations
1. only female students between the ages of 14 and 18 years from the Roswell area of New Mexico participated in the study;
2. the study was performed for eight weeks during the academic school year; 3. the testing was done outside on an all-weather rubberized track;
4. no one who had, or developed, chronic muscle pain or injury was included in the data analysis;
5. sprint testing only took place on days without extreme weather conditions. Risk/Benefits
A risk of the study was that any student might have become injured during the interventions. However, this risk was no greater than that occurring during everyday practices and/or activities during the physical education class. One potential benefit of the study for the participants was a decreased sprint time. Another benefit included knowledge of strength training methods for coaches/teachers to utilize a program that might be more
effective in improving sprinting performance. Significance of the Study
The significance of this study was to potentially inform physical educators of
effective training methods to improve the physical well being as well as performance of their students. The results of the study could influence students to achieve new levels in their overall physical performance and help physical education teachers by using these techniques to teach students how to improve their overall performance. This study will also contribute to the existing literature about effective training methods to increase sprint performance.
6 CHAPTER II Review of Literature
The purpose of this study was to examine the effects of both high-velocity (HV) and high-resistance (HR) training programs on overall sprint time performance in female high school students. Sections included in this review of literature are predicting sprint speed based on strength and power, effects of specific types of training on running form, strength training for adolescents, training method effects on sprint time performance, and summary. Predicting Sprint Speed Based on Strength and Power
It is assumed that more powerful athletes have faster sprint performance outcomes. Researchers have found mixed results, however, when predicting sprint speed based on strength and power measures (Cronin & Hansen, 2005; Smirniotou et al., 2008). Also, Baker and Nance (1999) studied various measures of strength and power on sprinting capability. Timed 10 m and 40 m sprints for 20 professional male rugby players were conducted over a week at the completion of preseason training. The distances of 10 m and 40 m are
comparable to the distance during play in the sport of rugby and many other sporting events and are thought to be indicative of the initial acceleration and maximum sprinting speed capability of athletes. The participants involved in the study had previously participated in a resistance and sprint training program for a minimum of four years which allowed for some familiarity with the resistance exercises that would be performed. On the first day of testing, the participants completed a three repetition maximum (3 RM) test by performing full squats and power cleans to measure strength. On the second day of testing, the participants
completed a timed sprint test over 10 m and 40 m along with a loaded barbell jump squat test for maximal power. During the barbell jump squat test, the athletes performed three
consecutive plyometric movements against loads ranging from 40 kg to 100 kg to test for power. Even though the researchers tested measures of strength and power, the results of this study showed that none of the exercises performed were significantly correlated to
performance in the 40 m sprint. However, strength and power exhibited a much stronger relationship when compared to the 10 m sprint time (Baker & Nance). The researchers concluded that there may need to be separate training strategies to improve running speed over the two distances for game play. This study also showed that specificity of training may be of more use than training for the sport as a whole when trying to increase speed over specific distances.
To determine which protocol works best, different distances have been used to compare training methods for various sport programs. The distances typically used are similar to those for plays within sports like football, soccer, rugby, baseball, and softball; however, no distance less than 100 m exists in the sport of outdoor track and field. Therefore, in the following study, the researchers used short distances to try and explain the amount of power a track and field athlete exerts during the start of a race. Young, McLean, and Ardagna (1995) examined the relationship between strength qualities and sprinting performance. Eleven male and nine female sprinters, hurdlers, and jumpers between the ages of 16 and 18 years participated in the study. An electronic timer was used to determine the sprint times at 2.5, 5, 10, 20, 30, 40, and 50 m along with two force platforms to record the horizontal and vertical reaction forces during the sprint start. The force platforms used during the sprint test measured the block time, resultant block velocity, resultant block acceleration, and maximum resultant block force and were placed under both the hands and feet during the block start. The subjects performed two maximum effort timed 50 m sprints from a block start, and the
fastest time was used for the data analysis. After the sprint tests were performed, power tests consisting of squat jumps, counter movement jumps, and platform jumps for maximum height were then conducted. The counter movement jumps involved execution of a dip immediately prior to the upward phase of the jump takeoff. Participants in the study also completed a jump test from a 120° knee angle with a 19 kg bar resting on the shoulders. This knee angle is reported to be within the range to produce maximum force for the knee
extensors and the angle is similar to the knee angle of the rear leg in the set position of the block start (Blount, Hoskinsson, & Korchemny, 1991). Results of the Young and colleagues study showed strength qualities, or power, were related to sprinting performance at both the start of the sprint and at maximum speed. (Note: the distance at which maximum speed is obtained differs among researchers and sprinters; therefore different distances are used in studies). Young and colleagues also found that the three best predictors of starting
performance were obtained during the concentric jumping test, counter movement jump test, and drop jump test, whereas the single best predictor of maximum sprinting speed was the force generated within the first 100 ms from the initiation of movement out of the blocks.
The previous studies indicated that specific strength training movements, like counter movement jumps, can predict the overall performance of the athlete; however, these training methods may affect running mechanics (Cronin et al., 2008). Strength measures, such as ones used by Young et al. (1995), may allow for enhancement of training programs and help coaches predict how fast their athletes may be. This knowledge should allow coaches to place athletes in the correct positions or events that relate to the sport in which they are participating. Research is still being performed to determine which strength training protocols work best.
Effects of Specific Types of Training on Running Form
Sprint running is described in three phases: an acceleration phase, a maximum speed phase, and a maintenance phase (Delecluse et al., 1995; Moir, Sanders, Button, & Glaister, 2007). The ability to develop maximal sprint speed in a short time may be of greatest significance when sprint efforts are of short duration. The athlete’s ability to accelerate is dependent on factors such as running technique (kinematics) and the force production of the lower limb musculature (Cronin et al., 2008). Understanding the athlete’s abilities allows coaches to design training exercises that use applied forces as resistance to improve force production while running different distances. Coaches and athletes use weighted vests, sleds, parachutes, tires and bungee cords regularly to improve leg strength and force production; however, the use of these objects may change sprint kinematics (Cronin, Ogden, Lawton, & Brughelli, 2007).
In 2007, Cronin and his colleagues enlisted the help of 20 athletes involved in competitive sports to determine what effect weighted vests and sleds had on trunk lean and foot strike. The participants were videotaped while running a 30 m sprint from a standing start with cameras placed at 5 m, 15 m, and 25 m from the start to provide a baseline measure of sprint kinematics. The subjects were also videotaped while wearing a weighted vest and pulling a sled performing the same 30 m sprint. Loads of 15% and 20% of body mass were chosen to examine the effect of heavier external loads on sprint kinematics. The sled’s base (7.2 kg) was attached to the athlete using a shoulder harness and a 2 m long rope. The vest consisted of a belt around the athlete’s waist with straps over the shoulders that were fastened at the back so the load could be added evenly around the front and side of the waist. Dual beam infrared lights connected to an electronic timer were placed at the start, 10 m, and 30 m
marks to measure sprint times during all trials including the un-resisted, sled towing, and vest wearing trials. The results of this study showed that the 30 m sprint times increased as the load of both sled and vest increased along with a step count increase through the acceleration phase of sprinting. The greatest influence on performance was found when towing a sled was compared with sprinting with a weighted vest. The results reflect the different manner in which the two techniques overload the body and therefore provide insight into possible different mechanisms by which vest and sled towing may act to improve sprint acceleration performance. The researchers also found that sled towing and vest sprinting both resulted in acute changes in sprint kinematics during the acceleration phase. Cronin and colleagues (2008) believed that sled towing may be a more appropriate training modality for the early stages of the acceleration phase of sprinting because the running mechanics are similar to that of normal block starts.
Sleds and weighted vests are common pieces of training equipment that many schools can provide to train their athletes without putting them in the weight room (Cronin et al., 2007). Bungee cords, tire pulling, and parachutes are also used to help athletes gain strength and improve performance by using resistance other than weights. These methods may be effective for improving strength but also can cause a change in the athlete’s kinematics while running by changing the angle of foot strike and trunk lean (Cronin et al., 2007). If coached properly, the athlete can use these techniques during the initial acceleration phase; however, the running mechanics are not the same throughout the rest of the sprint performance. In 2008, Alcaraz, Palao, Elvira, and Linthorne conducted a study on 11 male and seven female sprinters and jumpers between the ages of 17 and 26 years to compare kinematics of
three types of resisted sprint training devices (i.e., sled, parachute, and weight belt). The weighted sled was attached to the participant at the waist and was loaded with 16% of the participants’ body mass. A medium sized parachute (1.2 m x 1.2 m) was also used and was attached to the participant at the waist by a harness. Lastly, a weighted belt was loaded to 9% of the participants’ body mass and placed around their waist. The participants were given a 20 m run-in start to the actual trial distance of 30 m. This distance allowed the participants to be at top running speed during each weighted trial. The researchers found that the sled, weighted belt, and weighted vest were appropriate devices for training the maximum velocity phase in sprinting, even though an acute reduction in stride length and running velocity occurred. The parachute and sled produced the greatest kinematic change in the lower limbs and trunk causing the trunk to lean more and the participant to have a shorter foot strike distance. The researchers indicated that this is an adequate form of resistance training due to the improved sprint time; however, the trunk lean must be carefully monitored with resisted sprint devices so that an inappropriate angle is not induced or reinforced (Alcaraz et al.). When compared to Cronin et al. (2008) the studies had similar findings which suggest that training with sleds and weighted vest are beneficial for improving sprint time, but the athletes need to be monitored and corrected when their running mechanics change.
Training with resistance devices is a common program in many coaches’ regimens. Coaches should use them appropriately so the athlete experiences a large training stimulus which stresses the system to produce adaptation to improve overall physical performance. Coaches should guard against specific changes in the athlete’s forward lean and changes in the angles for the support leg during the foot strike (Alcaraz et al., 2008).
Strength Training for Adolescents
Researchers have used different combinations of sets and repetitions to study the effects of resistance training on young athletes (Faigenbaum, Milliken, Moulton, & Westcott, 2005). Faigenbaum (2000) described adolescence as a period of time between childhood and adulthood and includes girls between the ages of 12 and 18 years and boys aged 14 to 18 years. Training athletes in this age group has not been as extensively studied as training adults, and many questions and concerns arise when training younger athletes that include whether or not strength training can increase muscular strength in young athletes and the perceived high risk of injury (Guy & Micheli, 2001). The role of strength training for adolescents remains a topic of controversy due to misconceptions regarding the risks to younger athletes, such as a loss of flexibility and range of motion necessary for optimal performance in their chosen sport (Guy & Micheli). However, researchers have found benefits that refute the misconceptions, for example that strength training can increase flexibility and range of motion among children (Faigenbaum et al., 2005; Guy & Micheli).
It appears, however, that recommended training protocols for maximizing muscular strength in adults (i.e., heavy weight combined with low repetitions) might not be ideal for adolescents who could benefit from performing additional repetitions with a lighter load during the early phase of training (Faigenbaum et al., 2005). For example, Faigenbaum and colleagues (2005) studied the efficacy of pre-adolescent children 8 to 12 years old
performing lighter loads for 15 to 20 repetitions for eight weeks. The results indicated that higher repetitions resulted in greater gains in local muscular endurance and flexibility among children. However, in a later study conducted on pubertal boys, training with lower
Guy and Micheli (2001) believed that resistance training can result in marked strength gains in the prepubescent child which is helpful due to the increase in sports participation among younger athletes.
Competitive sports have increased in popularity among prepubescent children and raise many questions about the risk associated with weight training for those desired sports. Injuries are common in any activity and can be avoided in many cases; however, many injuries that occur during youth training are attributed to improper lifting technique and excessive loading (Guy & Micheli, 2001). Guy and Micheli believed that a better assessment of the risk associated with resistance training would come from studies of closely monitored and supervised training programs with properly prescribed training loads. Their conclusion was that the risks associated with resistance training are no greater than those of competitive sports given that the strength training program is properly supervised and the athletes are instructed correctly.
Free weights, weight machines, and exercises that use the body’s own resistance are different types of training that are used while strength training young athletes. Ignjatovic and colleagues (2007) examined the effects of strength training on young athletes for eight weeks. Twenty-one basketball players ranging in age from 14 to 15 years participated in a training protocol of three circuits of six repetitions for each of the different exercises
performed (but not listed in the study) for the lower back muscles, upper and lower body, and abdominals. In the first three weeks of training, two sessions per week were performed and during weeks three through six the number of training sessions increased to three. During the last two weeks of training, the sessions decreased to two per week. The researchers used isometric muscle strength tests (dynamometer and “Standing Leg/Sitting Calf Muscle
Extension”) that registered maximal voluntary contraction force. A video camera and motion analysis software were used to determine the height the participants produced during
maximal vertical jump. The researchers found that applied training for strength development led to an increase in maximal isometric force along with an increase in concentric force produced in leg extensions and calf extensions. Ignjatovic et al. concluded that strength training in young athletes resulted in an increase in maximal isometric muscle contraction and increased performance of the vertical jump of the participants.
Adolescent participation in strength training programs can be appropriate when the programs are designed well and competently supervised. Strength training not only provides improvement in sport performance but may provide the adolescents with a gain in self-confidence in their physical abilities so they will continue to participate in other activities as they get older (Ignjatovic et al., 2007).
Training Method Effects on Sprint Time Performance
Strength training has become a popular way for athletes to increase overall performance in sports. Many types of strength training methods are used by strength and conditioning coaches and athletes to increase speed, strength, and power. One popular method of weight training which requires athletes to lift heavy loads with few repetitions is called high-resistance (HR) (Delecluse et al., 1995). A second popular training technique is high-velocity (HV) training which can include plyometric exercises. Plyometric exercises use the athlete’s body weight as the resistance and include exercises such as bounding, hopping, skipping, and jumping. Some coaches and athletes perceive plyometric training as the only strength-training method to result in an improvement in sprint performance because coordination and speed are specifically related (Delecluse et al.).
Delecluse and colleagues (1995) found that training with heavy weights and low repetitions allowed the participants to increase sprint speed over short distances; however, a study performed by Faigenbaum et al. (2007) researched the effects of plyometric exercises added to resistance training in early pubertal boys to determine which program was more beneficial in improving strength and sprint times. Faigenbaum et al. (2007) hypothesized that six weeks of training the early pubertal boys with a combined resistance and plyometric training program would lead to greater improvements in fitness performance. Twenty-seven boys between the ages of 12 and 15 years were randomly placed in a resistance training (RT) group and a combined resistance and plyometric training (PRT) groups. Prior to the start of the study, the subjects were tested in a 9.1 m shuttle run, vertical jump, long jump, and seated medicine ball toss. Both groups then exercised twice a week for six weeks. The PRT boys participated in a plyometric training program that included jumping forward and backward, one and two leg hops, hurdle and cone hops, and dot drills. The PRT then joined the RT participants and performed additional resistance training of three sets of ten to twelve repetitions in the squat, front squat, and upper body resistance exercises. These exercises were to be performed in an explosive manner to emphasize maximum performance during the remainder of the training protocol. The RT group did not participate in plyometric exercises during this training intervention. At the end of the 6-week training program the participants' strength and speed were reevaluated using the vertical jump, long jump, seated medicine ball toss, and 9.1 m shuttle run test. The results found that while strength increased neither training program improved sprint performance. This was possibly due to the short sprint distance which did not allow the participants to reach maximum running velocity.
Improving the final sprint time performance is a goal of both coaches and athletes. As previously mentioned, the sprint consists of several components such as the initial
acceleration, and maximum speed, and maintenance phases (Delecluse et al., 1995, Moir et al., 2007). All three phases must be performed at a high level to maximize sprint time, and each phase requires different physical abilities for optimal sprint performance. Understanding the effect of resistance training on separate sprint phases is important when trying to explain how the strength gained may or may not have improved sprint performance. Moir et al. enlisted 16 male participants between the ages of 17 and 21 years who were physically active in sports including rugby, soccer, and basketball to participate in the study. Prior to the start of the training protocol, the researchers timed the participants in a 20 m sprint. During an 8-week resistance training program, two mesocycles, each four 8-weeks in length, were used. The first mesocycle emphasized a strength-endurance program consisting of exercises such as parallel squats, bench press, and power cleans which the participants performed for three sets of 12 repetitions. The second mesocycle emphasized the development of maximum strength, also a 4-week program, which consisted of three sets of five repetitions. Although the researchers listed no justification for the order of their prescribed mesocycles it does appear to represent principles of periodization training, which is when training is varied in intensity, type, and length of time. At the end of the 8-week study, sprint times were tested again over 20 m measuring the initial acceleration phase of the sprint. During this study Moir and collogues found increased maximum and explosive strength while also increasing
accelerative sprint time immediately after the training period. The study also concluded that potential benefits of increased muscular strength during sprints less than 30 m are likely to be affected by the running technique of the participant (Moir et al.).
Many different training programs are used to improve sprint time along with overall athletic performance; however, coaches are free to choose which one works best for their program. In 1995, Delecluse and colleagues compared the effects of HR and HV training on sprint performance. The researchers believed that HR training results in improved initial sprint acceleration without improving maximum speed whereas HV training, that includes movement specific plyometric exercises, would improve maximum running speed. The male physical education students included in the study had not taken part in an earlier strength training program. Sixty-six students between the ages of 18 and 22 years were randomly placed into four groups including HR, HV, run, and passive groups. Prior to the start of the study, all participants performed a pre-test in the 100 m, along with being tested for their 10 RM strength for bench press, leg press, half squat, leg extension, and arm curl. In
addition, the HV group was given a pre-test for bounding, hopping, the standing broad jump, and vertical jump to determine their maximum distances prior to the training period. These pre-tests allowed the participants to familiarize themselves with the exercises that were included in the training program. The run group participated in a running workout (not explained) with the other two training groups once a week to see if the running program alone would elicit a change in sprint times, while the passive group did not train at all. The intervention took place over the course of nine weeks. The results found by Delecluse et al. showed that HR training increased the participants’ strength levels, but the effect on sprint performance was only significant when compared to the passive training group. In addition, the results showed that training with an increasing load in this condition resulted in greater initial sprint acceleration but no significant improvement for other components or parameters of sprint performance such as continued acceleration and maintaining maximum speed. On
the other hand, the HV group was the only group to significantly improve in the 100 m time due to a gain in initial acceleration. Also, when compared to the HR group, the HV group was more efficient in improving initial acceleration and final sprint time.
The studies discussed found that different training protocols improved overall performance when used together but also found that specific training protocol improved certain phases of the sprint, not the overall sprint performance. However, Faigenbaum and colleagues (2007) showed that in order to improve the sprint performance as a whole the training protocol of HR and HV should be used together.
Summary
Specific strength and power measures can predict the speed of athletes over short distances such as the initial acceleration and maximum speed phases of the 100 m sprint. The training methods used to achieve power and strength output can also hinder the athlete’s performance by changing foot strike angles or trunk lean. These effects can cause an increase in time and injury if not properly supervised by trained staff during practices. Different training methods have also been studied to determine which works best among elite male athletes and boys of various ages; however, few studies relate to adolescent females.
Previous studies have shown that training programs containing HV exercises improve sprint time performance among males and younger athletes which will help coaches and athletes improve performance and conduct proper training programs. The findings of the studies on how training programs can improve specific phases were consistent, but researchers believed that the programs should be used together to improve the sprint performance, and that
should to be conducted to look at training programs among females as well as males to help achieve athletic success.
20 CHAPTER III
Methods Introduction
The purpose of this study was to examine the effects of both high-velocity (HV) and high-resistance (HR) training programs on overall sprint time performance in female high school students. Pre- and post-test 100 m sprint times were analyzed to understand the effects of HR training and HV training on 100 m sprint times among female students. Sections included in this chapter are participants, setting, research design, instruments, validity of study, procedures, analysis method, and summary.
Participants
In this study 30 females from Roswell, New Mexico, ranging in age from 14 to 18 years, were selected from a volunteer pool of students in the physical education classes at Roswell High School and Valley Christian Academy. The participants who were familiar with strength training programs were excluded from the analysis as this might have adversely affected the results. However, these adolescents were able to participate alongside their peers in the activities.
Setting
Training was conducted in the Roswell High School and Valley Christian Academy weight rooms with similar facilities and training machines. Testing was conducted outdoors on the track facilities on the Roswell High School campus. An athletic trainer was present at the time of training and testing to provide drinking water and see to any medical needs during the interventions. Testing did not occur on days when the wind speed exceeded 15 mph, during rain, or on days when the temperature was below 65° F or above 90° F.
Research Design
A quasi-experimental design was implemented. Due to the real-world setting, pre-test and post-test groups were created using matched pairs while as many threats to validity as possible were controlled. This design was used to analyze the mean change in sprint times at the end of the 8-week intervention to determine if the training programs had any effect on the participants’ times. The training protocol was the independent variable, and the change in sprint time performance was the dependent variable.
Instruments
Sprint speed was assessed using an electronic timing system manufactured by Equine Electronics, which measured time within 1/100th of a second. The electronic timing device sent a signal upon the release of pressure on the sensor pad to the handheld timing device. The device shut off once the participant broke the laser barrier. The electronic timing device was deemed acceptable for this study, but the timing equipment had unknown validity and reliability. The equipment was pilot tested to determine the feasibility of the testing equipment. The resistance training equipment that was used included a 45 lb weight bar, Smith squat machine, hamstring curl, hip extension and flexion on a weighted cable
machine, weighted seated leg press, and seated leg extension. Cones were also utilized during the plyometric exercises
The sprint testing procedure had face validity because the 100 m sprint is an actual race in track and field events.
Validity of Study
Possible threats to internal validity of this study were history, selection bias, and expectancy. History was a threat due to any events occurring during the experiment that were
not part of the treatment such as any extra training performed by the participants. The convenience sample that was used was a threat to internal validity; selection bias affects the ability to generalize as the location the participants were drawn from was not a full
representation of the female student population. Also, the fact that the researcher expected that one training program would enhance the participants’ sprint time in the 100 m was a threat to validity.
Procedures
Human subjects approval was obtained prior to the start of the study. After additional approval to conduct the study had been granted by the Roswell High School and Valley Christian Academy principals, and coaches/physical education instructors, a meeting was held to discuss and explain the study to parents and potential volunteers. During the meeting, the researcher asked the volunteers about their current knowledge and experience with strength training programs. This knowledge allowed the researcher to determine potential participants for the training intervention. The researcher also described the types of exercises that would be performed during the HR training program (i.e., leg press, leg extension, hip extension, hip flexion, hamstring curl, calf raise, and squat) and the HV training program (i.e., standing broad jumps, vertical jumps, cone jumps, skipping, bounding, and hopping). All participants and their parent/guardian signed informed consent forms (Appendix A) that were handed to the researcher before approval to join the study was given.
Before the two 100 m trials performed during the pre-test took place, the participants were notified of which day they would be needed based on alphabetical order. Based on the number of participants from each class period, the girls were divided into groups with a maximum of 10. The entire pre-trial took place over two days to provide ample time for
completion of both trials and not allow for too much rest (i.e., cool down) between each trial. For the pre-test and the post-test, the participants met at the Roswell High School track facility wearing shorts, t-shirt, possibly sweatpants and sweatshirt, and flat soled running shoes (spiked shoes were not allowed).
The electronic timing equipment was set up using a single lane on the track. The 100 m start and finish line were already marked on the track, and the pressure switch was placed at the starting line. The participants were shown how to start the square shaped pressure switch, the correct starting stance (three-point stance) and the proper technique to correctly finish the sprint. The participants were allowed to practice starting the electronic timing device and jogging through the infrared beam from a short distance of 20 m; once all 10 participants felt comfortable, the warm up activities began.
The participants were led through a warm up by the researcher that consisted of a 400 m jog followed by static and dynamic stretches including bounding exercises. Following the stretching, the individuals were allowed any additional warm-up activities they felt necessary before performing the 100 m sprint. At the conclusion of the warm up activities the
researcher moved the infrared beam, which stopped the timer, to the finish line. Each
participant ran individually starting from a three point stance. No starting blocks were used to avoid any familiarity with previously used equipment. Starting commands were similar to those used in competition, such as “on your mark,” “set,” and “go.” Each participant was individually assigned a subject identification number to keep track of the results and time in the 100 m. Each participant completed two timed trials with a maximum 15 minute rest period between each trial. The participant’s time was displayed on a digital hand held reader
held by the researcher at the finish line and the time was manually recorded with the best time for each participant being used in the data analysis.
At the conclusion of all pre-test trials, the sprint times were ranked from the fastest to the slowest time and participants were assigned to one of the two intervention groups, HR and HV, by way of matched pairs. The first two participants with the fastest times were placed in different training groups, then the next two participants were randomly assigned to the groups and so on until all participants were assigned.
After the pre-test in the 100 m dash was completed, the participants who were placed in the HR training group engaged in a strength test to find their 8 repetition maximum (8 RM) in each of the selected weight training exercises including leg press, leg extension, hip extension, hip flexion, hamstring curl, calf raise, and Smith machine squat. This test was performed over several days within the week following the 100 m pre-test. The results of the 8 RM tests were recorded for later use when the training sessions began.
For the next eight weeks the participants engaged in their respective training programs. For the first two weeks, training took place twice a week following which the training increased to three days a week. The HR group was directed to perform the exercises in a controlled manner and to execute them safely on the exercise machines. The participants were directed to lift three sets of their 8 RM. The HR training program exercises are outlined in Appendix B. Because adaptation to the weight training was expected, the researcher added weight as required to maintain the 8 RM as the student got stronger.
The HV group participated in a program of unloaded plyometric and agility exercises that emphasized the speed of movement. Unloaded plyometric exercises use the body and gravity as resistance while performing the exercises. This program also involved frequency
drills including standing broad jumps, vertical jumps, cone jumps, skipping, bounding, and hopping as outlined in Appendix C. A circuit involving the exercises was performed three or four times in succession.
A post-test for sprint time was performed in a similar manner to the pre-test at the conclusion of the 8-week intervention using the same timing device. At the end of the training and research period, the mean change in 100 m time was calculated for each participant (Appendix D).
Analysis Method
Data analysis was done using a paired t-test to examine whether a difference existed between the two groups’ mean change scores. The null hypothesis was that the HV training would not result in a greater improvement in sprint time when compared to HR training for high school female students. Alpha was set at .05 to control for type I errors.
Summary
Research has been performed using males of different ages and abilities to test different training methods to improve performance, but there is a lack of research relating to both adolescent females and physical education students. Studies have also been conducted to see what effects different exercises and equipment have on specific phases of sprint running, but few look at the sprint as a whole. This study was designed to test the effects of HR and HV training on overall sprint time performance in the 100 m among female physical education students. Participants of this study may not only benefit from the training by achieving a faster sprint time, but may also improve their overall physical performance on state mandated assessments.
26 CHAPTER IV
Results Introduction
The purpose of this study was to examine the effects of both high-velocity (HV) and high-resistance (HR) training programs on overall sprint time performance in female high school students. Pre- and post-test 100 m sprint times were analyzed to understand the effects of HR training and HV training on sprint performance among female students. Sections included in this chapter are descriptive statistics, data treatment, statistical analysis, and summary.
Descriptive Statistics
Female participants were selected from a volunteer pool of students enrolled in physical education classes at Roswell High School and Valley Christian Academy High School. Participants (N = 30) ages 14-17 years were assigned to two groups - the HV group (n = 16) and the HR group (n = 14) - using matched pairs as described in Chapter 3.
Table 1
Mean 100 m Performance Times of Female Physical Education Students
Age (years) Pre-test (s) Post-test (s) Change Score (s)
M SD M SD M SD M SD
HV 15.78 0.75 20.57 2.06 19.72 2.08 -0.85 1.10
Data Treatment
A between subjects design was implemented to analyze the mean change in sprint times at the end of the 8-week intervention to determine if the training programs had any effect on the participants’ times. All participants completed two trials of the 100 m during both the pre-test and the post-test and only the best trial time in each set was used for data analysis. The sprint times were measured using an electronic timing system, and all times were recorded to the 1/100th of a second. Preliminary review of the data suggested that training improved the 100 m sprint time regardless of the training protocol.
The pre- to post-test change scores were computed for every participant and were used to calculate the mean for each group. A paired t-test was then used to calculate the mean change score for each group to determine if there were any significant improvements
between the training protocols. Statistical Analysis
Data were analyzed using SPSS®Student Version 17 for Windows software to test the null hypothesis. The results showed no significant difference between the two groups’ mean change scores (F(1, 28) = 0.062, p > 0.05). Therefore, the null hypothesis, which stated that the HV training would not result in a greater improvement in sprint time when compared to HR training for high school female students, could not be rejected.
Since an improvement was observed between the pre- and post-test time for both groups, further analysis was needed to confirm whether the improvement was significant. A repeated measures ANOVA was used to analyze pre- to post-test data for all individuals in both training groups over the eight weeks of training. The within subjects results were statistically significant (F(1, 28) = 18.687, p < 0.001) showing that the eight weeks of
training induced a significant improvement in the sprint time performance regardless of protocol.
Summary
Based on the results, no significant difference was found between the two training groups’ mean change scores. However, both protocols over the eight weeks of training resulted in a significant improvement in the pre- to post-test times for 100 m.
29 CHAPTER V
Discussion Introduction
The purpose of this study was to examine the effects of both high-velocity (HV) and high-resistance (HR) training programs on overall sprint time performance in female high school students.Participants for the study were 30 adolescent females (M = 15.56 years, SD = .65 years) who were participating in high school physical education classes at Roswell High School and Valley Christian Academy. The participants had little knowledge and experience with strength training and completed an 8-week training protocol consisting of HV exercises or HR exercises. The data were analyzed to determine which training protocol better improved sprint time performance in this population.
This chapter discusses the results of the study and includes the following sections hypothesis findings, pre- and post-test comparisons, conclusions, and considerations for future research.
Hypothesis Findings
It was hypothesized that HV training would result in a greater improvement in sprint time compared to HR training for high school female students. Results showed that training improved overall sprint time performance in the 100 m dash; however, no significant
difference between the mean change scores for the two training protocols (F(1, 28) = 0.062, p > 0.05) was found.
According to current literature, a HV training program will improve sprint time performance in the 40 m and increase height during a vertical jump test (Chelly et al., 2010; Chimera, Swanik, Swanik, & Straub, 2004). Chelly et al. performed a series of exercises including counter movement jumps and squat jumps to assess the leg power of male soccer
players. For eight weeks the researchers had the participants complete the training during their regular season and found that plyometric training induced a significant increase in thigh muscle volume, a significant increase in squat jump and counter movement jump heights, and a significant increase in running velocities at 5 m and 40 m. Chimera et al. also evaluated the effects of plyometric training on the performance of the lower extremities during jumping exercises as well as the training’s influence on the stretch shortening cycle during running performance. The stretch shortening cycle is the stretching of the muscles before the contraction to produce a greater force during most jumping movements and is the basis for plyometric exercises. The researchers had 20 collegiate female athletes perform plyometric exercises twice a week for six weeks and found a significant increase in vertical jump height along with an improved sprint time. In the current study jump height was not measured, but the sprint time results are supported by the conclusions of Chelly et al. and Chimera et al. that running velocities among the participants may improve with plyometric exercises.
Several earlier studies have also shown that a HV training program can improve sprint time in a 100 m sprint or a 40 yard shuttle run when compared to, or in combination with, a HR training program (Delecluse et al., 1995; Faigenbaum et al., 2007). Delecluse and colleagues analyzed the effects of training on 100 m sprint performance among male physical education volunteers between the ages of 18 and 22 years for nine weeks. The authors
concluded that the HV group was the only training group to significantly improve the overall time in the 100 m sprint when compared to the other testing groups used in the study. Also, Faigenbaum and colleagues (2007) compared the effects of a 6-week training period of combined plyometric and resistance training and resistance training alone on fitness performance in boys between the ages of 12 and 15 years. The study found that combined
plyometric and resistance training significantly improved the vertical jump, long jump, and 9.1 m shuttle run, whereas the resistance training only protocol did not show significant differences in the performance areas that were tested. This suggests that a combination of the two training programs will significantly improve sprint time performance. The previously discussed studies support the finding of the current study that the participants’ sprint time will be improved with plyometric training; however, the resistance training results seem contradictory. The current study produced a significant improvement in sprint time among all of the participants, possibly because the students were not very active before the study
leaving room for an increase in performance. However, on several occasions a few students would not complete the required number of jumps. This may have affected the results among the HV training group when compared to the HR group.
Unlike previous research, the results of the current study show an overall improvement in the participants’ sprint performance for both training protocols. This improvement may not have been significant between the two training groups but when comparing the pre- to post-test times, the change was significantly greater.
Pre- and Post-test Comparisons
The length of a training program (i.e., number of weeks) may help reduce injuries if a significant change could be shown in a shorter amount of time. Research indicates that a minimum of eight weeks is needed to see training adaptations in performance; however, the optimal amount of time required is likely to be greater than ten weeks (Kravitz, 1996; Randell, Cronin, Keogh, Gill, & Pedersen, 2011). The present study was conducted over the course of eight weeks so the pre-test trials could be performed during moderate temperatures and post-test trials concluded before the end of the school year in mid-May. The results of
the present study suggest that a training period of less than ten weeks may induce a
significant change between the pre- and post-test sprint trials. The researcher acknowledges that both training protocols produced a significant improvement from the pre- to post-test trial sprint time, however, other outside factors may have influenced the outcome of the trials. The change in sprint time performance between the pre- and post-test trials could be due to a familiarity with the researcher and the participants being more comfortable with performing the running trials and the training protocols. Also, the pre- and post-training weight of the participants was not formally measured by the researcher, but fat loss could be a reason for the improvement seen in sprint time. Also, in conversation with some of the participants from the HR group indicated that muscle mass may have increased. This may indicate that the participant put on muscle mass and this gain could also be a reason for a significant improvement among the pre- to post-test times.
The sprint trials were conducted outside and with a tail wind, so the wind conditions may have affected the pre- and post-test trial times due to the seasonal wind speeds. It should be noted that sprint times considered to be “wind-aided”, for example greater that 8.95 mph (NCAA, 2011), are not counted toward the qualifying marks to compete at Nationals. Excessive wind speeds during the pre- and post-test trials were controlled for by the researcher in not allowing the participants to complete their trials if the sustained wind exceeded 15 mph. The pre-test sprint trials were conducted in sustained wind speeds of less than 5 mph for all participants, but averaged 12 mph during the post-test. However, the significant difference (p < .001) in sprint times between trials suggests that the improvement is unlikely to be due solely to increased wind speeds.
Conclusions
The experimental hypothesis was not supported in this study because it did not meet the set level of significance (p < 0.05) as a predictor of training protocol influence on sprint performance. Both training groups improved sprint time from the pre-test to the post-test within the eight weeks of training. It could be suggested that both training protocols can help students and athletes improve their sprint performance. Based on the information from this study it may be important for people involved in sprinting, coaching, and other sports to understand that a shorter amount of time for training, not only the training protocol, can produce an improvement in sprint time. However, it is unrealistic for physical educators and coaches to determine the effects of the training protocols on the sprint phases of their
students and athletes because they may not have access to the high speed video equipment and force platforms used by previous researchers. A select untrained population was used for this study; therefore, the results may not hold true for other populations such as children, older adults, athletes, or the general population who regularly train and are interested in overall wellness.
Considerations for Future Research
The findings from this study have generated new ideas that could be of interest to individuals involved in athletics, training, physical education, and in sports which require sprinting. This study could also provide information to coaches and athletes about training programs that will improve performance in the 100 m sprint.
Since both training protocols produced an improvement in sprint time, it would be of interest to compare a combination of both HR and HV protocols to determine the amount of significant change that may occur compared to HV training alone. Faigenbaum and
colleagues (2007) conducted a study which compared the effects of a 6-week training period of combined plyometric and resistance training and resistance training alone. The study found that the combined group made considerable improvements in the shuttle run compared to that of the resistance training group alone; therefore, combining the training protocols might provide insight for professionals for improving the speed of their athletes and students.
Also, this study only looked at females between the ages of 14 years and 18 years of age. It could also be of interest to examine other age groups within a different regional setting to determine if the training protocols will produce a significant change in sprint time. Many studies have been conducted on male participants who were soccer and elite sprinters, therefore, another consideration could be to look at female athletes as well. This study provides information not only about females, but also about regular physical education students for whom little research is available.
This study used specific training exercises to see if any change in sprint time would occur. A consideration would be to change up the sets, repetitions, and exercises used in the protocols to see which combination of exercise induces a greater change in the sprint time performance. For example, the students could perform more or fewer repetitions of the exercises, or add different plyometric jumping exercises (i.e., plyometric boxes, jump squats, and other bounding exercises).
Lastly, the length of the current study was only eight weeks of training. It would be of interest to see the minimum number of weeks that would induce a significant change in the sprint time performance based on the training program of the participants. This information might help professionals reduce injury among the population they are working with by
shortening the training time along with helping physical educators improve their students’ performance in class.
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INFORMED CONSENT FORM
Comparison of Strength Training Methods on Sprint Time Performance Your daughter is invited to participate in a research study to be conducted by Tracie L. Edwards. Your teenager is currently enrolled in the Roswell ISD physical education classes, and this new study will be conducted within this program. The purpose of the study is to examine the effect of two different strength training programs on 100 m sprint time performance among high school female physical education students. Your daughter was selected as a possible participant because she is in the age group of interest. The researcher will ask the volunteers about their current knowledge and experience with strength training programs. Data will be analyzed from volunteers who have no prior experience with strength training programs; however, if the volunteer has current knowledge of strength training programs they will be allowed to participate in the program but their data will not be used for analysis.
Specifically, I am asking for parent approval along with student approval to participate in the collection of 100 m sprint time data from your daughter and have her participate in one of two different strength training programs for 8 weeks. I will visit the school to ensure the students complete the training exercises for that particular day. An explanation of the procedure follows:
The procedure begins with student participating in an explanation of the timing equipment being used then various warm up (stretching) exercises. The students will then complete two trials of a 100 m sprint for their best time. During the timed trials each student will individually perform the 100 m while the rest of the participants while watching from the starting line. The students’ time will be kept confidential from everyone but the researcher and their identity will be coded. At the end of the timed trials all of the students will be randomly placed into two training groups to begin their strength training programs. The high-resistance training program includes exercises such as leg press, leg extension, hip extension, hip flexion, hamstring curl, calf raise, bench press, seated rows, and arm curls and the high-velocity training program includes standing broad jumps, vertical jumps, hurdle jumps, skipping, bounding, and hopping. For the next 2 weeks the students will participate twice a week in their assigned training program. At the end of the first two weeks the students will increase their training to three days a week. At no time will students be left unattended while the participating in the timed trials or during their training program. At
the end of the 8th week of training the students will complete two time trials in the 100 m sprint to
determine if their times have changed.
In addition, your daughter will need to wear the appropriate clothing and footwear to participate in this study and the proper exercise equipment will be used at all times.
There are no foreseeable risks or discomforts, above those that might be expected during physical
activity (fatigue or soreness), associated with collection of this data. Please note, any student who
expresses a desire to not participate in training on any occasion will be allowed to stop immediately and if the participant wishes to withdraw from the study at any time they will be allowed without any
repercussions. I plan to use information obtained from the sprint times in any way thought best for education and publication. I will present the results of this study to my committee and dean at the end of the semester. All data will be collected and stored in a confidential way (code lists will be kept in a locked cabinet), and the student’s results will be reported anonymously at all times.
By signing this form, you are agreeing to the participation of your teenager in these strength training programs. Your daughter’s participation or refusal to participate in the data collection will in no way affect her standing in school nor positively or negatively impact her grade in the physical education class. At the conclusion of the study, a summary of results will be made available to interested parents/guardians and educators. Should you have any questions or desire further information, please call Dr. Sarah Wall at (575) 562-2915 [[email protected]]. For more information regarding your rights as a subject you may contact the Dr. Darren Pollock, Chair of the Human Subjects Committee (575) 562-2862
HAVING READ THE INFORMATION PROVIDED YOU MUST DECIDE WHETHER OR NOT TO ALLOW YOUR DAUGHTER TO PARTICIPATE. YOUR SIGNATURE INDICATES YOUR WILLINGNESS TO ALLOW HER PARTICIPATION IN THE STUDY. Student Name (Print)_______________________________ Date________________
Parent/Guardian Signature___________________________ Date________________
