One of the major things that causes the differences is muscle balance. With sprinting, function largely tends to follow form. In other words, sprinting technique is largely dependent upon what muscles are strong and what muscles are weak. A lot of people have strength but they don't have balanced strength. They're strong in the wrong muscle groups, weak in the wrong muscle groups, and their running technique tends to reflect that. The main contributors to the sprint stride are the muscles of the quadriceps, glutes, and hamstrings. For technique and function to be optimal, the sprint stride should be posterior chain dominant. This means the prime movers should be the muscles of the glutes and hamstrings. A lot of people think the feet and calves are really important for all athletes, but the hips are what produce force. When the hips and hamstrings are the prime movers, the stride tends to be characterized by the sprinter being nice and smooth up on the balls of his feet with little knee bend at impact and without the appearance of lots of bending and pushing. His feet will tend to strike the ground right under his center of gravity. In contrast, when the quadriceps are excessively dominant or when the posterior chain is weak, the stride tends to be characterized by being back on the heels with lots of knee bend, lots of noise, and lots of pushing. People will bend their knees and get back on their heels in an effort to utilize their stronger quadriceps. They’ll also tend to reach out in front of their body with their plant leg and strike on their heels.
Take a group of athletes, get behind them, and simply watch them take off in a sprint. You can immediately tell which ones are which. A quadricep dominant sprint stride makes it difficult to sprint effectively particularly at top speeds. Therefore, in my opinion one should seek a posterior chain dominant sprint cycle.
Although it's difficult to get really accurate measures when assessing the balance between the quadriceps vs the posterior chain, it's probably safe to assume the average trainee has a ratio of about 70% quadricep to 30% hamstring strength ratio. This means the quadriceps are twice as strong as the hamstrings. Contrast this to elite sprinters, who
may lean towards a 60:40 hamstring to quadricep ratio. One simple way you can help assess your balance in this department is to compare your standing broad jump to a single leg triple jump. First measure your normal standing broad jump. Next, stand on one leg and execute 3 consecutive single leg jumps. The total distance of the 3 jumps should be approaching 2.5 to 3 times the distance of your standing broad jump.
Another assessment you can do is check the mobility of the quadriceps and rectus femoris. I have noticed one with excessively dominant quadriceps will tend to be very tight in these areas.** The rectus femoris is the muscle that attaches to your hip and runs straight down the middle of your thigh.
Rectus femoris
One simple way you can check mobility in this area is just reach back, grab your heel and pull it up to the butt. If the quads or rectus femoris are overly tight, pulling the heel up to the glute will often be difficult.
Good quadriceps/rectus femoris flexibility
Tight Quadriceps/rectus femoris (over-dominant quads)
Someone with this problem will really need to stretch the quads and rectus femoris at least twice a day for 20 seconds, utilize plenty of dynamic stretches, and get away from any quadricep dominant activity. ***
**A recent study also indicated that having excessively tight quadriceps and rectus femoris was the best predictor of knee pain.
*** Dynamic stretching will be covered further along in this manual.
Quad/RF stretch
How do we get a dominant posterior chain and how does a person become excessively quad dominant in the first place? Well, the quadriceps can NEVER be too strong, they can only be too strong for the other muscle groups. The quadriceps are important, particularly for the start of a sprint. However, if a person is either born with dominant quadriceps or does lots of squatting to the exclusion of all else they will often tend to develop some of these problems. One with excessively strong and tight
quadriceps, along with weak hamstrings, should, in my opinion, avoid most squat variations and use either deadlift variations or wide stance box squats as foundational strength training movements. ***
Box Squat
*** The box squat is much more of a glute and hamstring dominant movement.
What about people who don’t have tight quadriceps but do appear to have a weak posterior chain? That’s a group that will actually include the large majority of young athletes. Fortunately, that problem will remedy itself with time and proper training as I lay out in this manual. What about everyone else? Just make sure you ALWAYS prioritize hamstrings and glutes in your training. The best exercise for the glutes is the basic barbell squat, yet it's also the best exercise for the quadriceps. There's nothing wrong with developing strong quadriceps, you just gotta make sure the hamstrings stay in balance and mobility is maintained in the quads and rectus femoris. Glute ham raises, leg
curls, pull throughs, reverse hyper-extensions, good mornings, and sled drags, are all effective hamstring exercises and should be utilized.