Significance of Force Application in Max Velocity Sprinting, Part 13

We are back with the series on Force, Ground Contact and Sprinting, and once again, we have Kenta’ Bell again.

To review:

Part 2: Kenta Bell’s Force Application in Max Velocity Sprinting

Kenta Bell

Click here to go to PART 1 of Significance of Force Application in Max Velocity Sprinting on Foot and Ankle Usage


This article was written by Kenta’ Bell, a two time Olympian (2004, 2008) in the Triple Jump and the 2001 Gold medalist at the World Student Games in Beijing, China.  His PR is an impressive 17.63m (#9 on the all-time USA list) and he is also the 2003 & 2010 USA National Champion.  Visit his website or you can contact him directly at

In my previous article I began explaining how to prepare the body to transfer force into the ground and thus back to the body via the elastic stretch reflex inhibitors of the lower extremity. In this discussion we will look at three (3) of the five (5) most important muscle groups in human locomotion. As we have previously looked at the foot/ankle and the gastroc/soleus as groups one and two we now move up the kinetic chain. For this article we will look at how the Gluteus – hip flexor/extensor – knee stabilizers’ play a significant role in max velocity sprinting and maximum ground force application.

When trained appropriately and are well synchronized in their firing order via neuro-muscular coordination you can simultaneously get maximum vertical and horizontal ground forces. I know it sounds confusing right? Let me briefly explain it this way before I jump into the details of this article. As the hip extends the thigh accelerates down and back. The lower leg accelerates backwards and creates the illusion of pawing via the negative foot strike. The glutes simultaneously engage and triple extension of the hip-knee- ankle occur creating maximum vertical ground force. As previously mentioned think of the thigh as a hammer and the lower leg as a nail.

Lets look at this in more depth. I will be discussing the role of the Gluteus muscle group, hip flexor/extensor muscle group and the stabilizers of the lower thigh just above the knee.

Gluteus Muscle Group

This is the largest muscle group in the human body. The priorities of the gluteus are creating balance and stability along with thrusting the hips forward.

clip_image002If standing and you contract your glutes you will feel your hips automatically thrust forward. The contraction of the glutes also simultaneously activates the abductors and adductors. This in return creates greater stability and stance in full support when running and jumping. You also have to realize that as the hips press forward the extensor muscle of the hip elongates and extends down and back. Thus leading into the next area of focus the hip flexor/extensor.

Hip Flexor/Extensor Muscle Group

clip_image004 The primary function of this muscle groups is driving the knee/thigh up and also in driving the quadriceps/thigh down and back in sprinting. The hip flexor is automatically (involuntarily) engaged when the gluteus muscle group is contracted. In short hip extension and flexion are much like riding a bicycle. You drive thigh down which elongates the hip extensor, thus driving the leg down as force is applied through a stabilized foot and loaded Achilles tendon. Thanks to Sir Issac Newton we know the opposite reaction is the shortening of the hip flexor on the opposite side, which immediately and involuntarily recoils the swing leg in a pattern that follows the extending leg.

Knee Stabilizers (vastus & lateral medialis)

vastus & lateral medialis

The primary responsibility of the two muscles is stabilizing the knee joint when the foot is in full support on running strides and jumps. These are the outer and inner thigh muscles just above the knee. Many problems that occur in jumpers knee and knee problems in general can occur from both weakness or muscle tightness and imbalance in this region. I strongly support doing postural strength work such as band walks and single leg body weight squats to strengthen create even muscle tone in this area.

3 Drills to Improve

Now that I have highlighted this area, I will share some of my favorite exercises/drills to activate and stimulate these muscle groups. Anybody who knows me knows me will already know that I am a huge glute guy when it comes to strength training. Likewise, I like to build glute activation into the early part of my warm-up plans just after jump roping. I look at my warm-up plans a flight systems check just before taking off as opposed to many who think that it’s all about getting warm and working up a sweat.

I strongly believe that activating and pre-engaging the muscles and systems will ensure a more effective and efficient workout.

Following the Glute bridges I immediately follow with core activation via plank exercises working in the prone, supine, and saggital planes. This ensures that no energy will be wasted or lost in unwanted trunk rotation or hip flexion. My next moves are designed for hip extension, hip flexion and Thigh acceleration.

1. A-Skip

My version of A-skips is much more subtle and smooth than most. I don’t accelerate the foot to the ground nor do I lift or drive the knee up aggressively. I wait for my foot to make contact with the ground heel first and focus on pushing upwards through hip extension. This in return creates voluntary knee lift that is in sequence with the ground force application as you bridge the foot from heel to toe. This action focuses more on hip extension and front-side mechanics via knee-up, toe-up cue.

2. Reverse A-Skip

Although uncommon this action works to help strengthen and activate the hip-flexor. It is also excellent at improving agility, coordination, and foot placement as related to the center of mass. You will find it next to impossible to do this drill leaning too much forwards or backwards.

3. Skip for Distance

If you have previously viewed my how to bound video you have seen me cover regular skipping and skipping for height. Skipping for distance knee down the track and accelerating the thigh down and back. This aggressive knee punch coinciding with the thigh drive creates a strong hip thrust and glute activation. As the athlete becomes comfortable with the movement and better coordinated with the sequence the progression is a hard acceleration sprint off the skipping movement. Utilizing a broomstick or barbell supported on the shoulders can further enhance this skipping movement.

Jimson Lee

Jimson Lee

Coach & Founder at
I am a Masters Athlete and Coach currently based in London UK. My other projects include the Bud Winter Foundation, writer for the IAAF New Studies in Athletics Journal (NSA) and a member of the Track & Field Writers of America.
Jimson Lee
Jimson Lee
Jimson Lee
  • I have a question. As you mention you’re a glute guy. Nonetheless I read scientific articles by Ralph Mann (1986) and others that claim that harmstring is the prime contributor to sprinting and my experience is that it is true. The glutes are very important or course, but why don’t you highlight the harmstring’s role in your article?

    • I dont overly highlight the hamstring because you when doing most glute exercises you get a lot of upper hamstring activation. I do agree with you that the hamstrings are very important. In fact I found that most athletes are very imbalanced when it comes to the quad/hamstring ratio. My favorite hamstrings exercises are single leg ball curls, Towel curls, glut-ham machine and stiff leg deads. You will notice that is with all of the exercises listed above you get both hamstring and glute activation if done correctly. I also don’t overly emphasize the hamstring because I don’t want people trying to run fast by pulling with the hamstring and lower leg. In my opinion the hamstring serves more of braking action of the lower leg to stop it from over-extending and losing the lower shank at max velocity sprinting. If you look closely thats when most hamstring injuries occur. just before the thigh begins to accelerate the leg backwards.

  • New Studies in Athletics 1 (March 1995), Vol. 10, 29-49 Relative activity of hip and knee extensors in sprinting -implications for training by Klaus Wiemann and Günter Tidow

    As forward acceleration in sprinting is obviously produced by hip extension rather than knee extension (WASER 1985, LEMAIRE, & ROBERTSON 1989, AE et al. 1992), it seems plausible to suppose that
    the strongest hip extensor, namely the m. gluteus maximus (GM), takes a major part in this extension. However, there are some doubts concerning this supposition, because the GM does not function only
    as a hip extensor; it also rotates the thigh outward, especially when the hip joint is extended. This could cause a backward rotation of the pelvis on the side of the free leg during the support phase, which might hinder the long forward swing of the free leg. Furthermore, the GM also has an abducting effect on the leg – especially in the case of an angled hip joint. This could have a negative effect on the straight movement of the support leg from front to back. However, outward rotation and abduction would not be of any consequence in the sprint, if another muscle could act together with the GM, both to support the GM during the hip extension and also to neutralize the abducting effect of the GM. This task could be taken over by the m. adductor magnus (AM), especially by its superficial part, which has its origin exactly at the ischial bone, medially beside the origin of the hamstrings and inserts to the medial epicondyle

  • When my son runs there is an audible sound. He is told it is counter active to him running faster. He is already fast, but certainly could get faster. He is also told the reason for the noise is his hips are not forward and his foot is hittng the ground in front of him acking more like a break. Any advice on fixing this? I think it’s related to his hips.