Improving Sport Performance with Resisted Hip Flexor Training

by Bryan Barrett

Research on the importance of hip flexors along with resisted exercises of the hip flexors in a strength and conditioning program is limited. Hip flexors are a group of muscles that are significant in the gait cycle by actively flexing the hip in the swing phase. Starting with the iliopsoas, the prime flexor of the hip, and assisted by the rectus femoris, sartorius, and pectineus. The iliopsoas has been considered, "one of the body's most powerful muscles (1)," yet when looking at resistive exercise to increase sport performance, it's left out.

When looking at the swing phase of the gait cycle, the flexors of the hip contract concentrically which moves the free limb forward to heel strike. One would think the faster you get the free limb forward to heel strike, the more it would increase stride frequency and in turn increase the athlete's speed.

Although research on the hip flexors is limited, the University of Florida biomechanics lab took "forty-eight college age volunteers who were physically active but not trained sprinters over an eight week period of resisted hip flexor training with elastic tubing and found a decrease of 3.8% and 9.0% in the forty yard dash and twenty yard shuttle (2)." Those are impressive numbers in an eight week period, which begs the question: why not incorporate this type of training in your program?

When people think of training hip flexors, the rotary hip machine comes to mind. This machine can be used in strengthening, but when looking to improve sport performance, I like to stay functional and closed chained. Closed kinetic chain exercises, such as squatting or lunging, utilize both multiple-joint proprioceptive reactions and muscular co-contraction. For this reason, they are assumed to be a more functional intervention than open chain exercises (3).

Two exercises I like to use when targeting the hip flexors include the sled and resistance bands. The sled is a perfect tool that allows the athlete to incorporate sprint mechanics while using a heavy load to increase strength. The athlete starts with the pelvis anteriorly tilted and explodes the knee up. "The anterior pelvic tilt position provided the highest EMG activity in the rectus femoris. The anterior tilt may place the rectus femoris and underlying iliopsoas muscle group in a more optimal length position. This will change the muscle length–tension relationship and produce higher contractile forces(4)."

The following video demonstrates the correct way to use the sled for hip flexor training.

With the resistance bands, I feel it necessary to find middle ground between strength and hypertrophy. The resistance bands keeps it functional, and the athlete's main goal should be to drive the knee up fast as possible while keeping ground contact time minute. The main concern is increasing neural impulses so the tilt of the pelvis is indifferent. The following video demonstrates the optimal way to use resistance bands for hip flexor training.

References

(1) Dalley, F Dalley. Moore, L Keith. 2005. Clinically Oriented Anatomy 5th Edition. Lippincott Williams & Wilkins

(2) Deane, Russell. Chow, John. Tillman, Mark. Fournier, Kim.(2005). Effects of Hip Flexor Training on Spring, Shuttle Run, and Verticle Jump Performance. Journal of Strength and Conditioning Research. 19 (3), 615-621

(3) Irish, Sian E; Millward, Adam J; Wride, James; Haas, Bernhard M; Shum, Gary LK (2010).The Effect of Closed-Kinetic Chain Exercises and Open-Kinetic Chain Exercise on the Muscle Activity of Vastus Medialis Oblique and Vastus Lateralis. Journal of Strength & Conditioning Research. 24(5):1256-1262.

(4) Workman, Chad. Docherty, David. Parfrey, Kevin. Behm, David. (2008) Influence of Pelvis Position on the Activation of Abdominal and Hip Flexor Muscles. Journal of Strength and Conditioning Research. 22(5): 1563-1569