Should strength coaches stop using the hip thrust to improve sprinting performance?
Although it took quite a while for sprint coaches to adopt the use of strength training to develop their athletes, it is now commonplace, with the back squat being the most popular exercise. Indeed, many sprint coaches now display the same resistance to using new exercises as the previous generation did to adopting any kind of strength training.
Even so, several years ago, researchers identified that superior sprinting performances were determined more by the ability to produce greater force in a horizontal direction, rather than in a vertical direction.
Although vertically-directed forces are very high during a track sprint, they do not increase by as much as horizontally-directed forces as the running speed increases. Athletes increase horizontally-directed forces in order to accelerate, to overcome wind resistance, and to overcome the frictional forces that occur in the braking phase of the ground contact phase.
Once this discovery became widely-accepted, some strength coaches and researchers suggested that strength training exercises that involved producing force in a horizontal direction relative to the body (called an “anteroposterior” force vector) might lead to greater improvements in sprinting ability than traditional exercises like the squat, which involve producing force in a vertical direction relative to the body (called an “axial” force vector).
In the barbell hip thrust, extremely heavy weights can be used, and this makes progressive overload very easy to accomplish. Consequently, the hip thrust quickly became a popular “anteroposterior exercise” among strength coaches. It is often now programmed for improving the ability to produce force in a horizontal direction when sprinting, although there is actually a stronger case for using it to improve back squat and deadlift performances in powerlifting, but I will leave that idea for another day.
What is the hip thrust exercise?
The hip thrust is a glute bridge, but with the back placed against a bench instead of on the floor. Using a bench raises the upper body base of support, which allows a greater range of motion at the hip, and causes the external load being lifted to travel further.
When doing a glute bridge or hip thrust for athletic development, the exercise is most commonly performed with a barbell resting on the hips to provide external load. Such barbell loads can be very large, even greater than those used in deadlifts.
Compared with the glute bridge, the hip thrust tends to move the range of motion at the knee towards a more extended knee angle. This means that the quadriceps work at shorter average muscle lengths, while the hamstrings work at longer average muscle lengths.
The hip thrust involves the gluteus maximus and hamstrings to a greater extent than the back squat, and the quadriceps to a similar extent. Yet, it also involves a smaller overall range of motion. This means that the muscles are trained over a shorter range of lengths, and peak bar speed at each percentage of one repetition-maximum (1RM) is slower.
Can the hip thrust exercise improve sprinting performance?
Early research into the hip thrust exercise in adolescent athletes indicated that the exercise was superior for improving sprinting performance compared to the front squat.
Although critics were keen to point out that the front squat was used as a comparison exercise instead of the more popular back squat, this criticism was actually mostly unfounded, because the back squat and front squat are far more similar to one another than most people realize. In fact, the front squat only becomes marginally more hip-dominant than the back squat at the point when near-maximal loads are used.
Since then, two research investigations have failed to identify a benefit of using the hip thrust to improve sprinting performance in collegiate athletes, although neither study also tested the effects of the squat. A limitation of this approach is that we do not know whether any exercise would have enhanced sprinting ability in these subjects, as sprinting is a notoriously difficult quality to improve. Even so, it certainly suggests that the hip thrust exercise is not a “magic bullet” exercise that will improve sprinting performance in all athletes, regardless of how it is performed.
Indeed, it is noteworthy that both of these more recent investigations used fairly heavy loads, and one implemented a deliberately slow tempo during training. The other did not specify precisely whether a maximal bar speed or a slow tempo was used during training, and may therefore have not controlled this variable.
Using heavy loads leads to predominantly low velocity-specific strength gains, and can even reduce high-velocity strength in some athletes through the conversion of very fast (type IIX) to moderately fast (type IIA) fibers. Using a slow tempo means that strength gains cannot occur through increases in neural drive to the prime mover muscles. Thus, the only effects of that particular training program for sprinting would have derived from increases in muscle size, primarily in the gluteus maximus.
What does improve sprinting performance?
Sprinting ability seems to be determined by the ability of the hamstrings to absorb energy at long muscle lengths, of the hip extensors (gluteus maximus, adductor magnus, and hamstrings) to contract at high velocities while operating at short muscle lengths, and of the hip flexors to contract quickly through a full range of motion, all in a horizontal direction.
Therefore, it is the hamstrings that need to be exposed to very heavy loads (ideally while lengthening) in order to improve sprinting ability. In contrast, the gluteus maximus needs to be able to produce force very quickly, which means using light loads and a maximal bar speed, in order to develop explosive strength in that muscle. Explosive strength is primarily determined by early phase neural drive, but is also affected by properties of the muscle fibers themselves, which can be enhanced by high-speed contractions while avoiding fatigue.
This is probably why the heavy barbell hip thrust may not have produced the desired improvements in sprinting ability (while heavy back squats often do), because the shorter range of motion, heavy loads, and slow tempo (and therefore extremely slow velocity) would very likely have produced muscle growth in the gluteus maximus, but would not have developed its ability to perform high-velocity contractions.
Similarly, this is probably also why a number of investigations have identified the jump squat as one of the very best exercises for improving sprinting ability, because the very long acceleration phase (all the way through to the point when the athlete leaves the ground) has two key effects:
- It allows more high-velocity force to be exerted at short muscle lengths (at the point of take-off) compared to a conventional back squat, which is decelerating at this point; and
- It allows a higher velocity to be reached, and also encourages maximal intent to move the bar, both of which improve gains in explosive strength in the lower body muscles.
What is the takeaway?
When sprinting, the hamstrings need to absorb very high forces while lengthening, while the priority for the other hip extensors is to be able to produce force quickly.
This means that heavy barbell hip thrusts, which involve very slow velocities over a short range of motion may not be ideal for improving sprint running ability, especially when programmed with a slow tempo that prevents the development of explosive strength. However, it seems very likely that hip thrusts with a lighter load and a maximal bar speed would be able to enhance sprinting ability by increasing the ability of the gluteus maximus to exert force at short lengths, and at a high-velocity.