THE EFFECTS OF STATIC STRETCHING AND SELF-MYOFASCIAL RELEASE ON RANGE OF MOTION AND MUSCLE STIFFNESS: A COMPARATIVE STUDY
Helen Virginia Robertson
A thesis submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Exercise and Sport Science in the Department of Exercise and Sports Science.
Chapel Hill 2015
Approved By:
Claudio Battaglini, Ph.D.
Darin Padua, Ph.D.
ABSTRACT
“The Effects of Static Stretching and Self-Myofascial Release on Range of Motion and Muscle Stiffness: A Comparative Study”
“Under the direction of Dr. Claudio Battaglini”
Most people use static stretching as a way to loosen tight muscles and improve flexibility. This form of stretching has several positive benefits, such as increasing range of motion, reducing unnecessary muscular tension and soreness after exercise. Most recently, research has shown positive effects of self-myofascial release (SMR) using a foam roller on muscle stiffness, but it is limited to data looking at range of motion. Therefore, the purpose of this study was to examine the effects of static stretching and self-myofascial release on range of motion and muscle stiffness in the calf as an attempt to evaluate which method provided the best results on reducing muscle stiffness and range of motion. Twenty-five subjects who ranged in age from 18 to 28 years old came into the laboratory for testing on two separate days with no more than 5 days between visits. One day subjects performed 3 minutes of static stretching using an incline board and the other day 3 minutes of self-myofascial release using a foam roller. Range of motion (ROM) and muscle stiffness was assessed using an isokinetic dynamometer immediately following the stretching techniques. Each session was randomized and counter balanced to reduce the influence of a learning effect. Dependent samples t-tests were used to compare the changes (Δ=Post-intervention– Pre-intervention) on muscular stiffness and ROM. There was no significant difference between static stretching and foam rolling for max ROM (5.37± 3.88 and 4.72± 3.38 respectively, p=0.50), Stiffness at 15˚ (0.025± 0.283 and 0.366 ± 1.225 respectively, p=0.06) and stiffness at 80% of maximum ROM (0.063± 0.255 and 0.163± 0.617 respectively, p=0.43). In conclusion, static stretching and SMR using a foam roller are effective at increasing ROM and decreasing stiffness but neither one appears to be superior to the other. Thus, based on the results of this study, static stretching and SMR could be used interchangeably to increase ROM and decrease stiffness.
TABLE OF CONTENTS
CHAPTERS
I. INTRODUCTION………...………..1
Statement of purpose……….……..…………..………....3
Research questions………..………..………...3
Hypotheses………..………..………...…..……..3
Operational definitions…..………....3
Delimitations……….…....………..4
Assumptions………..……….…..….………….…...4
Limitations………...………...…..…5
Significance of Study………..……….…....5
II. REVIEW OF LITERATURE………..………...7
Application of stretching……….……….……….7
Foam rolling technique……….………...9
Muscle relaxation techniques………...13
III. METHODOLOGY………..………..…………15
Study design………...………..…………...15
Participants………..………15
Instrumentation………..………...……...16
Assessments………...………...………..…….………….……..16
Exercise intervention……….……….17
Data reduction…….………..………..………….….……....18
IV. RESULTS………..………..………...20
V. DISCUSSION……….……….25
Range of motion………..26
Stiffness………28
Summary………...….….31
Recommendations for future research………..……….…..31
Conclusion………...32
REFERENCES………...……….….34
LIST OF TABLES
Table Name Page
Table 1. Sample Descriptive Statistics ……… 20
Table 2. Descriptive Statistics of Tests Performed at Day 1 and Day 2 Pre and Post Interventions………21
Table 3. Descriptive Statistics of Changes (Post-pre static stretching and self-myofascial release Interventions) in ROM and Muscular Stiffness at 15˚ and Stiffness at 80% of Maximum ROM…….……….21
Table 4. Results of the Paired Samples T-Tests Performed to Compare Baseline Values of ROM and Muscular Stiffness Prior to the Static Stretching and Self-Myofascial Release (SML) Interventions………....22
Table 5. Results of the Paired Samples T-Tests Performed to Compare Change in ROM and Muscular Stiffness between the Static Stretching and
Chapter I
INTRODUCTION
Traditionally, static stretching has been commonly used to alleviate muscle tension and as a warm up but recently, foam rolling has become a popular
alternative. Foam rolling has been shown to increase range of motion similarly to static stretching but tends to have longer lasting effects.
Exercise causes small micro tears in the muscle, which generally results in adaptation through muscle size growth. A side effect of this is that scar tissue may build up in the muscle and lead to dysfunction (Healey, Hatfield, Blanpied, Dorfman, & Riebe, 2014). Restrictions in the fascia from injury, disease, inactivity, or
inflammation may also cause dysfunction. The restrictions cause the fascia to become inelastic and dehydrated, which in turns creates fibrous adhesions. These adhesions decrease range of motion, muscle length, strength, and coordination and are also painful (MacDonald, Penney, Mullaley, Cuconato, Drake, Behm, & Button, 2013).
Most people use static stretching as a way to loosen tight muscles and improve flexibility. This form of stretching has several positive benefits, such as increasing range of motion, reducing unnecessary muscular tension after exercising, and decreasing soreness after exercise. Not stretching and therefore having tighter muscles and decreased flexibility puts a person at a higher risk for injury
number of sarcomeres in series, which occurs due to the pressure on the muscle’s origin and insertion points. Decreases in force and performance have been seen with static stretching, so it is slowly becoming less popular as a warm up
(MacDonald et al., 2013).
For many years massage was used to break up the scar tissue and relax the muscles; however, within the past decade, self-myofascial release (SMR) has grown in popularity as an alternative to massage, among other uses. Self-myofascial release is most commonly performed using a foam roller. A person uses his or her body weight on the roller to put pressure on various soft tissue sites (Healey et al., 2014). He or she would use short, kneading like motions to roll up or down the muscle from origin to insertion or vice versa. This technique stretches the muscle and warms the fascia, causing it to become more fluid like and therefore decreases adhesions and scar tissue. The thixotropic property of the fascia is responsible for the changes in viscosity (MacDonald et al., 2013).
Statement of the Purpose:
The purpose of this study was to compare the effectiveness of self-myofascial release and static stretching in reducing stiffness and increasing range of motion in the calf muscle of apparently healthy and recreationally active male and female individuals.
Research Questions:
RQ 1. Is self-myofascial release more effective than static stretching at increasing calf range of motion?
RQ 2. Is self-myofascial release more effective than static stretching at reducing calf muscle stiffness?
Hypotheses:
H1. There will be no significant difference in range of motion of the calf muscle between static stretching and self-myofascial release.
H2. Self-myofascial release will cause a greater decrease in calf muscle stiffness as compared to static stretching.
Operational Definitions:
Stiffness: change in torque divided by change in position (relationship
between stress and strain).
Stress: internal force in relation to cross sectional area.
Strain: amount of deformation the body undergoes due to stress.
Effectiveness: increased range of motion and decreased stiffness of the calf
muscle.
Self-myofascial release: involves applying a sustained pressure on a muscle in
order to release myofascial restrictions.
Foam roller: the foam roller used was a multilevel rigid roller.
Static stretching: targeted muscle is held at it’s maximum length that does not
cause pain for an extended period of time with the goal of increasing flexibility.
Range of motion: the full movement potential of a joint; range of flexion to
extension.
Delimitations:
Subjects for the study were 25 males and females between the ages of 18 and 28 years old.
Subjects were required to be free of any lower leg injury or dysfunction. Subjects were required to be recreationally active (exercise but did not
compete at a competitive level).
Each stretching protocol involved 3 total minutes of stretching (either static stretching or self-myofascial release).
Assumptions:
The various forms of exercise the subjects participated in outside of the study did not affect their response to stretching.
Limitations:
The amount of stretching a subject performed on his or her own outside of the study.
Potential differences between subjects in the density and composition of the tissues in the calf muscle.
Pain tolerance when subjects executed the self-myofascial release technique may have hindered their ability to fully release adhesions in the calf muscle.
Significance of the Study:
Range of motion of the ankle has been correlated with injury risk in several studies. Static stretching increases the number of sarcomeres in series, which does not change the mechanical property of the muscle. If it can be shown that self-myofascial release changes the actual muscle properties, causing a decrease in stiffness and an increase in range of motion, injury risk can be decreased. This technique can then be integrated into training programs to be used in combination with or even replace static stretching in order to yield more positive benefits and adaptations of the muscle. Currently, most literature has examined the chronic effects of self-myofascial release and not the acute effects. Most studies also just measure range of motion with a goniometer, which does not give any indication of the impact of stretching techniques on the properties of the muscle. No studies to
Chapter II
REVIEW OF LITERATURE
For the purpose of organization, Chapter II will be organized into the
following sections: I. Applications of stretching; II. Foam rolling technique; II. Muscle relaxation techniques; IV. Summary.
Section I. Application of Stretching
Properties of the hamstring muscle during stretch were assessed in a study
conducted by Magnusson (1998). An isokinetic dynamometer was used to
determine resistance to stretch, which was defined as passive torque. The
researcher simulated a static stretch by extending the knee to a specific position and
holding for 90 seconds or extending it to a point of discomfort, which was the
stretch tolerance. Viscoelastic stress relaxation was represented by torque decline
in the static phase of the stretch. One static stretch was found to cause 30%
relaxation and multiple stretches resulted in more relaxation, but relaxation was
temporary. The increased range of motion seen after several weeks of stretching
was attributed to the subject having a higher stretch tolerance, rather than a change
in property of the muscle, however, it was noted that range of motion does not
assess the material properties of the muscle. Magnusson also noted that strength
training caused greater muscle stiffness, which was unaltered by regular stretching.
shown that at the same joint angle, there is a decrease in resistance or that at the
same resistance, a greater joint angle can be achieved (Magnusson, 1998).
Therefore, this study aimed to show that foam rolling does cause a change in
material property of the muscle as assessed using an isokinetic dynamometer.
Another study looked at the calf muscle in older women with limited
dorsiflexion in order to examine stretch and release characteristics. Position,
stiffness, and energy were examined. It was concluded that the older women had a
shortened calf muscle, limited range of motion, and decreased energy and passive
force, but increased stiffness. The researchers used a Kin-Com isokinetic
dynamometer to passively stretch the calf. The subject’s knee was fully extended
and then the foot and ankle was secured to an apparatus. Straps were in place to
hold down the subject’s leg and foot. The medial malleolus was aligned with the axis
of rotation on the apparatus. The dynamometer then dorsiflexed the foot at 5
degrees/second until a maximum stretch was achieved. The end of point of range of
motion was defined as just prior to the point that caused pain (Gajdosik, Linden,
Mcnair, Riggin, Albertson, Mattick, & Wegley, 2004). The protocol described in the
aforementioned study was followed for this research project.
Stretching is commonly recommended to prevent injury and improve
flexibility, leading to an increase in performance. The influence of static stretching
on viscoelastic properties was studied to determine if stretching would be a method
for increasing energy during exercise that incorporates a stretch-shortening cycle.
Researchers used a dynamometer to flex the foot to 35 degrees and that position
stretching led to reduced passive tension, stiffness, and viscosity as well as changes
in series and parallel elastic components of the muscle. The changes in
viscoelasticity of the muscle may be a reason for delayed contraction post stretching
(Kubo, Kanehisa, Kawakami, & Fukunaga, 2001). This study did not look at the
results of myofascial release, so it is paramount that these are compared. The
findings also lend support to the basis for the current research investigating the
effects of stretching.
Young and Behm (2003) looked at the effects of static stretching on force
production. As part of their research, each subject did static stretching then rested
for two minutes before performing a concentric jump and a drop jump. Of all warm
ups the researchers tested, static stretching showed the lowest values for the jumps.
They concluded that performing static stretching before a force activity hindered
performance and suggested that another form of stretching should be investigated
(Young & Behm, 2003). Though force production is not being measured, the current
research will hopefully show a similar or better effect of self-myofascial release as
compared to static stretching, which would indicate further research needing to be
done on using self-myofascial release as a warm up.
Section II. Foam Rolling Technique
Myofascial release is commonly used in physical therapy but not much research has been done to look at the effectiveness of this stretching technique. One study looked at myofascial release of the hamstrings and quadriceps as compared to static stretching of the quadriceps. Each stretching technique was done for 8
minutes and then muscle stiffness, range of motion, and reaction time were measured using a durometer, goniometer, and an electromyogram and Biodex system respectively. No differences were seen in muscle stiffness but range of motion was increased in all the stretch groups. Reaction time was also lower after the myofascial release, which led the researchers to conclude that myofascial release improves ease of movement in addition to increasing range of motion (Kuruma, Takei, Nitta, Furukawa, Shida, Kamio, & Yanagisawa, 2013). Based on the results, it is important to re-examine muscle stiffness and range of motion in a less complex muscle and using a dynamometer to increase accuracy.
Researchers have examined the effects of self-myofascial release on range of motion to determine if force or muscle activation were decreased after foam rolling (MacDonald, Penney, Mullaley, Cuconato, Drake, Behm, & Button, 2013). They discussed how foam rolling could loosen fascia that had become inelastic or
dehydrated. Myofascial release works on the thixotropic property of fascia, breaking up adhesions by the friction from the foam rolling warming up the fascia and
causing it to become more fluid-like. It has been determined that using a foam roller made of harder material yields better results due to the increased pressure on soft tissue and a smaller surface will lead to a more isolated contact area. Therefore, in the current study a firmer foam roller with knobby projections was selected to both increase pressure and isolate restrictions. Eleven male subjects participated in the study. Both before and after foam rolling several measurements were taken:
performed two, 1 minute sessions of foam rolling the quadriceps, then
measurements were taken two minutes after and ten minutes after. A control condition was also performed where subjects did not foam roll but measurements were still taken. For the foam rolling protocol, it was determined that there should be constant pressure on the muscle for 60-90 seconds. Subjects were instructed to use short kneading like muscle to work down the quadriceps then roll back to the hip and repeat the process for one minute, then rest 30 seconds, and then repeat the protocol for a second time. It was suggested that within the minute of foam rolling, subjects roll slowly so that the subjects rolled down the quadriceps 3-4 times within the minute. Range of motion was assessed using a goniometer to look at knee angle while subjects were in a lunge. It was found that foam rolling did increase knee range of motion, likely due to the change in thixotropic property of the muscle. Researchers suggested that further research be done comparing the difference between foam rolling and static stretching on range of motion since static stretching has been shown to reduce muscle force but foam rolling does not. Based on the results and suggestions of the MacDonald et al. (2013) study, the current research aims to compare static stretching and self-myofascial release in terms of both muscle stiffness and range of motion. The current study also based the foam rolling protocol on the protocol stated in the MacDonald study, and followed suggestions about the type of foam roller to use.
Another study compared self-myofascial release and the Graston technique in terms of range of motion and neuromuscular activity (Blackburn, Petschauer, Frank, Begalle, & Gibb, 2012). The researchers were examining whether the changes
due to foam rolling were due to tissue modifications or neurophysiological
properties. The comparison between the change in muscle force and the change in length is defined as muscle stiffness. The factors affecting stiffness are neural drive and mechanical factors. A higher stiffness implies the muscle is more resistant to change in length. The foam rolling technique used was to find restrictions in the muscle and hold pressure on that point using the foam roller for 90-120 seconds then find the next restriction and repeat the process. Subjects performed one minute of a general scan, one minute of a targeted scan of lateral and medial gastrocnemius heads, two minutes of 30 second holds on restricted areas, one minute targeted to the MT junction and Achilles tendon, then one minute general scan to total 6 minutes of foam rolling. An instructional video was shown to the participants to standardize performance. Range of motion was measured using a standard digital inclinometer. Muscle stiffness data could not be analyzed but
Healey, Hatfield, Blanpied, Dorfman, & Riebe (2014) examined whether or not self-myofascial release would enhance performance on athletic tests. The researchers suggested a warm up effect as the reason for the previously seen benefits of foam rolling. Participants consisted of 26 healthy college aged
individuals. At the beginning of each testing session, the participants performed a standardized dynamic warm up of lunges, walking knee to chest, side squats, walking butt kicks, Frankensteins, and penny pickers. Subjects then either
performed planking or foam rolling for 2 minutes and 30 seconds. The quadriceps, hamstrings, calves, latissimus dorsi, and rhomboids were rolled. The Foam Roller Plus was used because it was similar to the multilevel rigid roller, which had been previously shown to yield the best results. After the intervention, subjects
performed the vertical jump height and power tests, isometric force test, and pro agility test. Researchers found that foam rolling did not enhance performance, however, fatigue was significantly less than when subjects performed a plank prior to exercise. Therefore, the current study used a multilevel rigid foam roller and did not do a warm up prior to stretching.
Section III. Muscle Relaxation Techniques
Spernoga, Uhl, Arnold, & Gansneder (2001) looked at how long the hamstring
maintained flexibility after stretching. The intervention consisted of 5 hold-relax
stretches for a total of 5 minutes. After the intervention, measurements of flexibility
were taken at 0, 2, 4, 6, 8, 16, and 32 minutes. Stretching increased hamstring
flexibility for 6 minutes, which the researchers concluded was due to the
viscoelastic, thixotropic, and neural properties of the muscle. One session of PNF
stretching did not deform the tissues enough to produce a permanent change, which
means that elastic and not plastic regions of the muscle are affected. After stretching
while the muscle is relaxed, more stable bonds between actin and myosin filaments
form, which affects the thixotropic properties of the muscle, causing it to become
more gel-like rather than the liquid consistency during motion. The initial increase
in range of motion was likely due to autogenic inhibition blocking muscle activity,
which is transient. Based on the results and conclusions, the current research
incorporated foam rolling in hopes that there would be a longer lasting stretch
result that could be investigated in further research.
Malliaras, Cook, & Kent (2006) found that restricted range of motion of the
ankle may increase risk of injury. The study examined 113 volleyball players on
several factors including sit and reach flexibility, ankle dorsiflexion range, jump
height, plantarflexor strength, activity level, and years of competitive volleyball
playing. Dorsiflexion was measured with a weight bearing lunge test and was the
only factor that was associated with patellar tendinopathy. Injury risk was increased
by 1.8-2.8 times when players could not go dorsiflex further than 45 degrees.
Researchers concluded the increased risk may be due to a restricted ability to
absorb force. Limited range of motion could be due to inversion ankle sprain, tight
calf muscles, or inherent ankle joint stiffness. Based on the results of this study, if
foam rolling could increase range of motion and decrease muscle stiffness, it could
Chapter III
METHODOLOGY
Study Design
This was a pre-post intervention study that examined the acute effects of two different flexibility techniques (static stretching and self-myofascial release) on range of motion and stiffness of the calf muscle in college-aged subjects.
Participants
Twenty-five males and females between 18-28 years of age who were free of any lower leg injury or dysfunction and recreationally active (exercise but did not compete at a competitive level) were enrolled in this study. Subjects visited the UNC Neuromuscular Research Laboratory on two separate occasions lasting ~ 20
minutes in duration. On each visit subjects were assessed to identify trigger points based on four criteria. The presence or absence of trigger points was noted. The two visits consisted of either a static stretching or self-myofascial release protocol and there were no more than five days between each session. Each session was
Instrumentation
The following instruments were used for performing the stretching and foam
rolling techniques. A multi angle slant board (ideal products,Oshkosh, WI ,USA) with
angles of 20, 25 and 30 degrees was used for the static stretching protocol. A
multilevel rigid roller (MRR; Collins Sports Medicine, Raynham, MA) was used for
foam rolling purposes. The ROM and stiffness were assessed using a Humac Norm
isokinetic dynamometer (CSMI Medical Solution, Stoughton MA), with a customized
footplate that allowed for the foot to be secured to the plate through full ROM.
Assessments
Each subject was assessed for trigger points in the right gastrocnemius and soleus. Four criteria were used to detect a myofascial trigger point, and two must be met to qualify as a trigger point (Grieve et al., 2011). They are as follows: 1) A palpable band taught within the skeletal muscle, 2) A hypertensive tender spot/module within a taut band, 3) Recognition of current pain complaint by pressure on the tender nodule, and 4) Painful limit to full stretch range of motion (Travell and Simons, 1993; Gerwin et al., 1997).
the malleoli so that they did not impede any passive foot movement). The dynamometer lever arm passively dorsiflexed the foot at an angular velocity of 5°·sec-1 until the participants maximum tolerable ROM was reached then immediately returned to -20° of plantar flexion.
Passive stiffness was quantified using a fourth-order polynomial regression model that was fit to the gravity corrected passive angle-torque curves generated during the passive ROM assessment according to the procedures described by Nordez et al.(2008). Passive stiffness values (Nm·deg-1) were determined at 15° dorsiflexion, and at 80% of maximum ROM.
Exercise Intervention
The static stretching was performed using an incline board. The subjects
stood with the right foot on the incline board and then leaned forward with their
knee straight until they reached a maximum amount of tension without pain. This
position was held for 1 minute. Subjects then stepped off the incline board for 1
minute then repeated the process of a total of 3 minutes (2 sessions of 1 minute of
stretching). Range of motion and stiffness were measured immediately following the
3 minutes of stretching.
A Multilevel Rigid Roller was used to conduct the self-myofascial release technique, following a study protocol conducted by Healey et al. (2014). The right calf was rolled for two, one-minute bouts with one minute of rest in between bouts. Subjects were instructed to cross the left leg over the right leg and roll the foam roller down the calf using short kneading like motions. The starting position for the
foam roller was at the base of the knee and it was rolled all the way down to the ankle then quickly rolled back to initial position. Subjects were told to roll down the calf 3-4 times within each minute. Range of motion and stiffness were measured immediately following the 3 minutes of foam rolling.
Data Reduction
The torque and position signals were recorded simultaneously with a Biopac data acquisition system (MP150WSW, Biopac Systems, Inc., Santa Barbara, CA). The torque (Nm) and position (°) were sampled at 2 KHz. All digitized signals were stored on a personal computer (Think Pad T420, Lenovo, Morrisville, NC) and processed off-line with custom-written software (LabVIEW 8.5). The torque and position signals were filtered with a low pass (10 Hz) zero-phase shift 4th order Butterworth filter, cutoff frequencies of 50 – 2000 Hz. Passive stiffness was quantified using a fourth-order polynomial regression model that was fit to the gravity corrected passive angle-torque curves generated during the passive ROM assessment, according to the procedures described by Nordez et al.(2008). Passive stiffness values (Nm·deg-1) were determined at 15° dorsiflexion, and at 80% of maximum ROM.
Statistical Analysis
All data were gathered and entered into an electronic database for analysis.
The alpha level was set to a priori at 0.05 for all analyses. All statistical analyses
were performed using SPSS, a statistical software, version 19.
Hypothesis 1: There will be no significant difference in range of motion between
static stretching and self-myofascial release. Hypothesis 1 was analyzed by
comparing ROM delta scores (Δ=Post-intervention ROM score in degrees – Pre-intervention ROM score in degrees) between static stretching and self-myofascial release obtained via an isokinetic dynamometer, using a dependent samples t-test.
Hypothesis 2: Self-myofascial release will cause a greater decrease in stiffness as compared to static stretching. Hypothesis 2 was analyzed by comparing calf muscle stiffness delta scores ( =Post-intervention stiffness score in Nm·degΔ -1 –
Pre-intervention stiffness score in Nm·deg-1) between static stretching and self- myofascial release obtained via an isokinetic dynamometer, using a dependent samples t-test.
Chapter IV
RESULTS
The purpose of this study was to compare the effectiveness of self-myofascial release and static stretching in reducing stiffness and increasing range of motion in the calf muscle in apparently healthy and recreationally active males and females between the ages of 18 and 28. All data were entered into an electronic database for analysis. All data were analyzed on SPSS version 19.0 for Windows, a statistical software program. An alpha level of 0.05 was used for all statistical procedures, and descriptive statistics were presented in the form of means and standard deviations. Subjects
Twenty-six subjects, ages 18-28 years old (Mean = 20.8, SD = 1.79; Males n=6 and Females n=20) were enrolled in the study and completed the study protocol. All of the subjects were students from the University of North Carolina at Chapel Hill, were apparently healthy, and participated regularly in physical activity. The subject’s characteristics are presented in Table 1 below:
Table 1. Sample Descriptive Statistics
Variable N Range Minimum Maximum Mean DeviationStd.
Age 26 9 19 28 20.8 1.79
Height (cm) 26 30.6 147.2 177.8 166.7 8.2
Intervention Testing Results
Descriptive statistics on the baseline (pre-intervention) and post-intervention scores as well as changes (Post – pre static stretching and
self-myofascial release interventions) in ROM and muscular stiffness at 15˚ and Stiffness at 80% of Maximum ROM are presented in Table 2 and 3 below:
Table 2. Descriptive Statistics of Tests Performed at Day 1 and Day 2 Pre and Post Interventions
Variable N Range Minimum Maximum Mean DeviationStd.
ROM Pre SS 26 48 98 145 115.44 12.030
ROM Post SS 26 47 99 147 119.94 12.146
Stiffness at 15˚ Pre SS 26 4 -1 3 .49 .942
Stiffness at 15˚ Post SS 26 5 -2 3 .75 1.081
Stiffness at 80% of max
ROM Pre SS 26 2 0 2 .55 .558
Stiffness at 80% of max
ROM Post SS 26 3 -1 2 .64 .699
ROM Pre SMR 26 35 96 131 112.75 9.886
ROM Post SMR 26 36 99 134 118.34 10.237
Stiffness at 15˚ Pre SMR 26 4 -2 3 .17 .856
Stiffness at 15˚ Post SMR 26 5 -2 3 .31 .887
Stiffness at 80% of max
ROM Pre SMR 26 2 -1 1 .21 .386
Stiffness at 80% of max
ROM Post SMR 26 3 0 3 .34 .596
SS-Static Stretching Intervention; SMR=Self-Myofascial Release Intervention; ROM= Range of Motion; Max=Maximum
Table 3. Descriptive Statistics of Changes (Post-pre static stretching and
self-myofascial release Interventions) in ROM and Muscular Stiffness at 15˚ and Stiffness at 80% of Maximum ROM
Variable N Range Minimum Maximum Mean DeviationStd.
Delta ROM Static Stretching
(Degrees) 26 15.62 .1490 15.77 5.37 3.88
Delta ROM SMR
(Degrees) 26 13.10 -1.789 11.31 4.72 3.38
Delta Stiffness at 15˚ Static Stretching (Nm·deg
-1) 26 1.33 -.6960 .63 .025 .283
Delta Stiffness at 15˚ SMR
(Nm·deg-1) 26 6.93 -2.58 4.35 .366 1.22
Delta Stiffness at 80% of maximum ROM Static
Stretching (Nm·deg-1)
26 1.28 -.23 1.05 .063 .255
Delta Stiffness at 80% of maximum ROM SMR
(Nm·deg-1) 26 3.18 -1.11 2.07 .163 .617
Delta= scores obtained by subtracting post-intervention minus baseline test scores; ROM= Range of Motion; SML= Self-Myofascial Release
The results of the analyses performed to compare baseline values of ROM and muscular stiffness prior to the static stretching and self-myofascial release (SML) interventions are presented in Table 4.
Table 4. Results of the Paired Samples T-Tests Performed to Compare Baseline Values of ROM and Muscular Stiffness Prior to the Static Stretching and Self-Myofascial Release (SML) Interventions
Paired Samples T-Tests Paired Differences
Mean DeviatioStd. n Std. Error Mean 95% Confidence Interval of the
Difference t df value
p-Lower Upper Pair 1
(ROM) 2.694 10.642 2.087 -1.605 6.992 1.291 25 .209
Pair 2 (Stiffness
at 15˚) .324 .865 .170 -.026 .673 1.908 25 .068
Pair 3
at 80% of maximum
ROM)
ROM= Range of Motion
Significant differences in muscular stiffness at baseline prior to testing at 80% of maximum ROM between the static stretching and self-myofascial release testing trials were observed (.55 ± .558 and .21 ± .386, p = .01, respectively).
Hypotheses Testing
The results of the paired samples t-tests evaluating changes in ROM and muscular stiffness between the static stretching and self-myofacial release using foam roller are presented in Table 5 below:
Table 5. Results of the Paired Samples T-Tests Performed to Compare Change in ROM and Muscular Stiffness between the Static Stretching and Self-Myofascial Release (SML) Interventions
Paired Samples T-Tests Paired Differences
Mean DeviatioStd. n Std. Error Mean 95% Confidence Interval of the
Difference t df value
p-Lower Upper Pair 1
(ROM) .6585 4.922 .9653 -1.33 2.64 .682 25 .50
Pair 2 (Stiffness
at 15˚) -.3412 1.129 .2214 -.797 .115 -1.541 25 .06
Pair 3 (Stiffness at 80% of maximum
ROM)
-.0996 .6395 .1254 -.358 .158 -.795 25 .21
ROM = Range of Motion
Chapter V
DISCUSSION
Range of Motion
There was no significant difference between static stretching and self-myofascial release using a foam roller for maximum ROM even though both
methods increased ROM. Similar results were found where there was an increased range of motion post long term static stretching in the Magnusson (1998) study; however, Magnusson attributed the increase to an increase in stretch tolerance, not a change in muscle properties (Magnusson, 1998). Though this conclusion was draw, data on the property of the muscles (i.e. stiffness) would be needed to support the claim that the material properties of the muscle were not affected.
Kuruma et al. (2012) found that active and passive range of motion were increased after stretching and self-myofascial release. Kuruma and colleagues concluded that increases were due to realignment of the fascia in the quadriceps and hamstrings to allow for a greater degree of knee flexion. The researchers did not compare the change in range of motion between the interventions, which would have been an interesting comparison. In another study, MacDonald et al. (2013) found that foam rolling the quadriceps resulted in increased range of motion at the knee joint, without decreasing force production. Knee joint range of motion was measured at 2 minutes and 10 minutes post the foam rolling intervention, which consisted of two, 1-minute sessions of rolling the quadriceps with one minute of rest in between sessions. The same protocol was used in the current study, though MacDonald did not compare foam rolling to static stretching techniques. MacDonald and colleagues also determined that after foam rolling there was no longer a
rolling is a method of stretching that appears to not negatively affect performance. Furthermore, MacDonald and colleagues attributed the increase in ROM to a change in the thixotropic property of the muscle, due to foam rolling warming up the fascia, causing it to become more fluid like, and breaking down scar tissue. Duration and force of the stress application were two factors speculated by MacDonald and colleagues that were important to the changes observed in the muscle. Although the shorter duration of 2 minutes of stretching was generally lower than in similar studies, the force of the subjects body weight was great enough to still cause the fascia to become more gel like. MacDonald and colleagues also recommended, based on the results of the study, that static stretching should be eliminated from warm ups due to the damage it induces of sarcomeres and the subsequent decrease in muscle force production. Since self-myofascial release changes the properties of the muscle rather than placing pressure on the origin and insertion points of the muscle like static stretching, it does not damage the sarcomeres and therefore also does not negatively affect force production. This means that since static stretching and foam rolling appeared to have had similar affects on range of motion and stiffness in the current study, it can be speculated that it would be better to choose foam rolling as a warm up strategy over static stretching, as there is not a decrease in force
production and it is less likely to damage sarcomeres. However, with the goal of promoting muscle tension alleviation and increasing ROM in tight muscles post training or competition, the current study showed that either static stretching or SMR using the foam roller produced similar effects.
Stiffness
For the purposes of this study, stiffness was defined as the change in torque divided by change in position, the relationship between stress and strain. There was no significant difference between static stretching and foam rolling for stiffness at 15˚ or stiffness at 80% of maximum range of motion. In earlier research, Magnusson (1998) found that a repeated static stretching caused a decrease in muscle stiffness, however, results only lasted an hour. Magnusson attributed the brevity of the response to the increase in tolerance, not a change in the material property of the muscle; however, it was not demonstrated in Magnusson’s study that a decrease in resistance could be attained at the same joint angle or the same resistance at a larger joint angle; if this could be demonstrated, it would be possible to concluded that a change in material property of the muscle was the cause of the decrease in muscle stiffness. In the current study, it was hypothesized that SMR using a foam roller would produce a greater decrease in muscle stiffness and even though no significant difference between groups was observed, it approached significance (p=0.06) at 15˚. Though not statistically significance, the difference in means between the change seen with static stretching (0.025 Nm·deg-1) and SMR (0.366 Nm·deg-1) are of clinical relevance because a greater decrease in stiffness occurred using the foam roller than static stretching. Likely there was less of a difference at 80% of maximum ROM because at that point, the muscle is stretched almost to it’s full extent, which would cause it to be stiffer than at 15 degrees.
if subjects were initially screened for limited dorsiflexion, stretching and foam rolling may make more of a difference for subjects with limited ROM than for the general population. Kubo et al. (2001) found that static stretching led to decreased stiffness by increasing the elasticity of the tendon structures. Instead of directly measuring stiffness, the researchers used ultrasonography to look at the elongation of the tendon and aponeurosis of the medial gastrocnemius, which could cause differences in results. Kubo and colleagues concluded that tendons and muscles are quite compliant and that the type of stretch may be a key factor in whether or not a decrease in stiffness is found. The researchers also suggested that their results indicate changes in both series and parallel elastic components in response to stretching. In another study examining strategies for decreasing muscle stiffness, Kuruma et al. (2012) did not find significant changes in stiffness before and after the stretching and self-myofascial release interventions. Each intervention lasted 8 minutes although the protocol used in the study did not provide detailed
information, hindering the readers’ ability to make conclusions on the effects of the intervention on reducing muscle stiffness. The way the subjects stretched or their method of myofascial release could have been the reason the researchers did not find significant results for stiffness. Stiffness was measured with a durometer instead of an isokinetic dynamometer, which could potentially add to the non-significant findings. To further the science and fill the gap on measuring muscle stiffness, one of the potential issues when evaluating muscle stiffness, the current study used isokinetic measurements. Contrary to Kuruma and colleagues, significant improvements in muscle stiffness were observed from pre to post interventions.
Therefore, the way stiffness is measured in an important factor to consider in future investigations. Some previous methods of assessing muscle stiffness may not be sensitive enough to identify potential changes in muscle stiffness. Consequently, based on the results of the current study, the use of an isokinetic dynamometer is recommended.
The protocol followed for foam rolling may have impacted results. In the current study, the protocol was modeled after the one used by MacDonald and colleagues (2013). Subjects performed a total of two minutes of foam rolling with one minute of rest in between sessions of foam rolling. Subjects were instructed to roll down the right calf slowly, 3-4 times within the minute. In this technique the foam roller is continuously moving, as opposed in other techniques where it is held still on a restriction for a given length of time. Blackburn and colleagues (2012) instructed subjects to foam roll for a total of 5 minutes, however, the foam roller was not moving continuously. During the first minute, subjects performed a general scan of the muscle and the second minute was a targeted scan of the lateral and medial heads of the gastrocnemius. During the next two minutes, subjects held the foam roller on restrictions they had found during the scan. Pressure was applied to the restriction for 30 seconds, then the foam roller was moved to the next
Summary
The purpose of this study was to determine if static stretching or self-myofascial release was more effective at decreasing muscle stiffness and range of motion in the calf muscle. An isokinetic dynamometer was used to measure both stiffness and ROM before and after the stretching interventions. Each subject completed two minutes of static stretching on an incline board and two minutes of foam rolling on separate days. Results showed no significant difference between the two stretching techniques, however, an increase in ROM and reduction in muscle stiffness were observed using static stretching and SMR with a foam roller. Therefore, it was concluded that both static stretching and foam rolling increase range of motion and decrease muscle stiffness similarly.
Recommendations for Future Research
Similar study with athletes (football players) as subjects. Athletes are more likely to have fascial restrictions than the general population due to exercise. Similar study with gymnasts as subjects. Gymnastics are flexible, so they may
benefit more from foam rolling than static stretching.
Similar study with individuals with restricted ROM, who would most benefit from a stretching intervention.
Potentially adding a third group where a combination of static stretching and self-myofascial release could be compared to the two techniques in isolation. Explore different volumes of the intervention; the amount of training that is
necessary for the self-myofascial release to be as effective as possible.
Modify self-myofascial release protocol to hold the foam roller on restrictions rather than continuous rolling.
Similar study protocol with a different muscle group other than calves, such as hamstrings.
Similar study with stiffness and ROM measurements taken at various time intervals after stretching intervention to see if static stretching of self-myofascial release leads to longer lasting results.
Add EMG measurements prior to assessing ROM and stiffness to ensure that subjects’ muscles are fully relaxed and not producing unnecessary tension that could skew results.
To begin investigating the chronic effects of the two interventions since an
acute bout of stretching may not be enough to produce clinically significant alterations on stiffness of the muscle.
If the dose-response relationship can be determined, looking at the amount of force and time of myofascial release needed to cause the most desirable changes in the fascia allowing for greater release of stiffness.
Conclusion
interchangeably. Since previous research has shown negative effects associated with static stretching, such as decreased muscle force production and damage to
sarcomeres, self-myofascial release would likely be a better choice of stretching technique prior to training or competition.
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