The # 1 Lower Body Strength Exercise to Improve Horizontal Acceleration (Part I)

This article is guest blogged by Karsten Jensen, M.Sc. Exercise Physiology, and a Strength and Conditioning Specialist.  Visit his website at

In the early 2000’s I worked with The Danish National Badminton Team, which consisted almost exclusive of players at the world class level.

At that time, we used mainly bilateral Barbell Squats and bilateral barbell dead lifts as lower body strengthening tools. Single leg exercises were also a part of the program.

Both both bilateral squats barbell squats and bilateral barbell deadlifts are safe, when performed correctly with appropriate loading.

Each player who used these lifts performed the exercises with correct form and with a gradual progression.

Despite the above precautions a number of players, over a period of months, got short term back injuries that both the players and the physiotherapist ascribed to the dead lift practice.

As they physio and I discussed the matter, my only explanation was that often they players had to perform their strength training in a fatigued state due to a very high amount of badminton practice (8 x 2 hours per week). On top of the badminton practice, almost every player had educational commitments, a mandatory part of the Danish sport system.

I still remember my heart skip a beat, when the physio and the doctor together more or less forbid me to place barbell squats or deadlifts in the training program!

How was I supposed to help these players develop leg strength, if I could not use the most productive barbell lifts?

Well, they were two against one and the players did in fact get injured! The lifts that work in many situations for many athletes simply were not the right solution for these players.

I often cite this experience as my last “letting go” of any emotional attachments to any exercises.

(For more on the importance of no emotional attachments see “Beyond Functional Training” – How To Maximise The Transfer of Exercises Through Science Based Exercise Selection)

I no longer remember my exact thoughts, but I remember deciding to make the best of it.

The emphasis with regards to lower body exercises was switched to Single Leg Squats, Single Leg Dead lifts, Step Ups, Multi Directional Lunges and Walking Lunges Dragging A Sled. Bilateral Barbell lifts were virtually eliminated from the program.

No one ever asked to get them back!

In badminton most men as well as the most explosive females perform vertical jumps, and we included jump training for some of those players. However, badminton also has a strong horizontal component, where the player accelerates from the center of the court, towards the corners. Then decelerates with balanced, perform the specific shot before accelerating again, back towards the center of the court.

Lunges that are performed on the same spot, emphasize the ability to decelerate in the corner and push back towards the center of the court.

Walking Lunges Dragging A Sled emphasizes the acceleration from the center of the court towards the corners.

The effectiveness of Walking Lunges Dragging A Sled in order to improve horizontal acceleration for badminton players (or any athlete) can be understood by considering Newton’s Third Law.

According to Newton’s Third Law action equals reaction.

If an athlete’s needs to accelerate horizontally, she must apply an action force that has a component that is parallel to the ground in a direction opposite the intended direction of movement.


The resultant force is angled down and back and can be separated in a vertical as well as a horizontal component (see above). The vertical component supports necessary levels of friction so the foot does not slide backwards, when the athlete accelerates.

To practice creating an action force that has a significant horizontal component, the most specific exercises involves practicing against a horizontal resistance.

This is stated in one of The Principles of Dynamic Correspondences that emphasize the importance of correspondence with respect to direction and amplitude of movement. (1)  The Principles of Dynamic Correspondence as well as other principles of exercise transfer are discussed in depth in Beyond Functional Training from the link above.

Another great example relates to running with respect to the use of barbell back squats or walking lunges dragging a sled.

In the barbell squat the accentuated force region is close to the bottom of the squat (the hip joints are in flexion) and the lower extremities produce a vertical action force into the ground.

The accentuated region of force production is “the region (joint angle) in a movement, where maximum dynamic force is expressed. (2)

In sprinting on the other hand, except for the action in the start block and possibly the early acceleration phase, the accentuated region of force is close to 0 degrees of hip extension and the lower extremities produces a horizontal action force.

Strength improvement in the Barbell Squat does have a correlation to running speed. (3) The correlation is weaker with respect to a 200 m performance compared to a 100 m performance, which supports the notion that squat might be more important for the acceleration phase and less important for top-speed and speed endurance. (4)

Thus, both barbell back squat and walking lunges dragging a sled are relevant exercises to a sprinter, with the latter exercises being more biomechanically specific, particularly to the top speed phase and speed endurance phase.

During the winter of 2009-2010, 55 year old 400 m runner Steve Millward used Walking Lunges while Dragging A Sled (tied to a belt around the waist) to reduce his 400 meter time from about 1m 30s to 1m 7 s. In 2012, Millward won the Ontario Veteran Championships in 400m in 62.07, still using walking lunges dragging a sled as staple in his strength training program.

Also certain martial arts have a component of horizontal acceleration and can benefit from variations of walking lunges while dragging a sled or being resisted by a belt.


  1. Siff M. The Means of Special Strength Training. Supertraining. Chapter 4, p 241. Supertraining 6th Ed. Supertraining Institute. Denver USA. 2004
  2. Siff M. The Means of Special Strength Training. Chapter 4, p 243. Supertraining 6th Ed. Supertraining Institute. Denver USA. 2004
  3. Comfort, Paul; Haigh, Andrew; Matthews, Martyn J. Are Changes in Maximal Squat Strength During Preseason Training Reflected in Changes in Sprint Performance in Rugby League Players? Journal of Strength & Conditioning Research. 26(3):772-776, March 2012.
  4. Bondarchuk A. Transfer of Physical Abilities When Using Different Types of Exercises. Chapter 2, p 75. Transfer Of Training In Sports. Ultimate Athlete Concepts. 2007

About the Author

Karsten Jensen (Msc Exercise Physiology, CPTN-CPTM, CHEK 2, HLC 3, USUI REIKI 1) is Strength and Conditioning  Specialist, and Founder of  The Flexible Periodization Method is the FIRST complete method of periodization, dedicated to MAXIMIZING results through a PROVEN 9-Step sequence to create truly INDIVIDUALIZED training programs.

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
  • Actually the little lesson of physics didn’t convinced me at all…Or I do not understand very well the language… I’m not sure that the resultant force during the acceleration is the one shown here…