About the author:
Roland Claes has a deep knowledge of performance optimization and trains elite athletes on a daily basis in his ESP training facility in Belgium
Chiropractor (Doctor of Chiropractic – USA)
Official representative for Belgium to the Fédération Internationale de Chiropratique du Sport (FICS – Lausanne, Switzerland)
Certified expert on exercise physiology, performance conditioning, and sports science – USA
Founder & owner of ESP I Elite Sport Performance
What muscles are most important for sprinting ?
When it comes to training a sprinter, there are lots of competing views, but one thing that all coaches agree on is that excess bodyweight is a bad thing.
Heavier sprinters only succeed at an elite level if their added mass is solid muscle, and then only when that extra muscle helps them sprint faster. So figuring out which muscles are most important for improving sprinting performance is critical.
A good way to do this would be to look at muscle sizes in sprinters and to compare them with non-sprinters. However, we can also make some educated guesses based on insights drawn from the biomechanics of sprinting.
Here are some insights (and then we will look at the muscles).
Insight #1: net joint moments
Net joint moments can be calculated during sprinting using motion analysis and force plates. They tell us what the turning forces are at each joint, and how these contribute to the overall system.
Early research indicated that the hips might be the most important muscles for sprinting ability. Mann (1980) observed in a group of elite sprinters that the best athletes displayed the greatest hip extensor and knee flexor net joint moments.
Later research confirmed this, as the percentage increases in hip extension net joint moments with increasing running speed were greater than the percentage increases in knee extension net joint moments (Simpson & Bates, 1990; Belli et al. 2001; Kuitunen et al. 2002; Schache et al. 2011).
In other words, the hip extensors get proportionally more involved with increasing speeds (Beardsley & Contreras, 2014).
You can see this in the chart below:
Changes in joint moments with increasing running speed
Insight #2: electromyography (EMG)
EMG is often misused and misunderstood, mainly by researchers who do not properly appreciate that the relationship between EMG amplitude and muscle force is not sustained under fatiguing conditions. Yet, in the right hands EMG is a valuable tool for assessing muscle activation changes with increases in running speed.
Several studies have reported that hip extensor muscle EMG amplitudes are high during sprinting (Jönhagen et al. 1996) and that their activity increases steeply as running speeds increase to sprinting (Mann et al. 1986; Wiemann & Tidow, 1995; Bartlett et al. 2014).
For example, Bartlett et al. (2014) found that EMG amplitudes in the superior and inferior regions of the gluteus maximus increased by 166% and 111% from walking to running, and quite dramatically by 562% and 451% from walking to sprinting.
Most importantly, some researchers have observed that some of the hip extensors increase their muscle activity with increasing running speed by more than the other muscles. Both Kyröläinen et al. (1999) and Kyröläinen et al. (2005) found that the muscle activity of the hamstrings increased more than the other leg muscles, with increasing running speed.
Insight #3: computer modelling
Very recently, biomechanical research methods have advanced to the point where detailed computer models are possible and can provide further insights, by drilling down to the level of individual muscle forces (Dorn et al. 2012; Schache et al. 2014; 2015).
An early model built by Dorn et al. (2012) set the scene for future research. They found that there was a muscular strategy shift as running speed increases, with muscle forces at the hip, primarily the iliopsoas, gluteus maximus and hamstrings, becoming very important for increases in running speeds above 7m/s.
More recently, Schache et al. (2015) investigated changes in joint work and joint contribution to overall power generated or absorbed by the lower limb across various different steady-state speeds (from walking at 1.59 ± 0.09m/s to sprint running at 8.95 ± 0.70m/s), in experienced sprinting athletes.
They found that the relative contribution of the hip to work done and average power generated and absorbed in the stance phase increased substantially, when comparing jogging and sprinting, as shown in the chart below:
Changes in the role of the hip with increasing running speed
What does this mean for muscular development?
Based on the original analyses of sprinting as a movement, later assessments of net joint moments, and recent computer models of internal muscle forces, it seems that sprinting performance is largely determined by the strength of the hip muscles, probably followed secondly by the knee muscles.
Even so, previous research has only partly confirmed this idea.
Many years ago, Kumagai et al. (2000) found that muscle thicknesses of the top part (but not the bottom part) of the anterior (r = 0.38) and posterior (r = 0.45) upper thigh were weakly associated with better 100m performance in a group of elite male sprinters. However, they also found that gastrocnemius muscle thickness (r = 0.36) was also weakly correlated with better sprinting ability, which was slightly unexpected.
More recently, Bex et al. (2016) compared the muscle volumes of the upper thigh and lower leg between national and international level track sprinters and endurance runners. They found that the sprinters routinely displayed larger hip and knee muscles than the endurance runners (by 14 – 21%), but not all of the muscles of the lower leg were different.
The upper thigh muscles are shown in the chart below.
Sprinters have larger hip and knee muscles
More interestingly, Bex et al. (2016) found that there was a strong association between the ratio of hamstring-to-quadriceps muscle volumes and International Amateur Athletic Federation (IAAF) score among the sprinters (r = 0.81), but not among the endurance runners. This indicates that having proportionally more developed hamstrings relative to the other leg muscles may be advantageous for sprinting performance, as has previously been noted (Morin et al. 2015).
Of course, we expect sprinters to be more muscular than normal people anyway. If the hips in general are important (and not just the hamstrings), then we should find that sprinters have even more disproportionally large hip muscles in comparison with normal people.
The study: Adding muscle where you need it: non-uniform hypertrophy patterns in elite sprinters, by Handsfield, Knaus, Fiorentino, Meyer, Hart & Blemker, in Scandinavian Journal of Medicine & Science in Sports (2016)
What did the researchers do?
The study measured the muscle volumes of high-level track and field sprinters, and to compare these with non-athletes, to see whether some muscle groups are substantially larger than others. This may help identify which muscle groups are the most important for sprinting.
The researchers took measurements as follows:
- Muscle volumes – using a magnetic resonance imaging (MRI) scanner, moving from the twelfth thoracic vertebra to the ankle joint, and assessing 35 muscles in both lower limbs.
- Normalized muscle volumes –by standardizing all muscles by an arbitrary unit of body size (the product of bodyweight and height).
The subjects comprised 15 NCAA Division I track and field athletes (7 males and 8 females), aged 18 ± 0.6 years. Of these athletes, 4 competed exclusively in 60, 100, 200, and 400m sprinting events; 3 competed in both sprint and hurdle events; 5 competed in sprints and jumping events (long jump and triple jump); and 3 competed in sprints, hurdles, and jump events.
In addition, a non-sprinting control dataset was used from a previous study that involved 24 recreationally active individuals (8 females and 16 males), aged 25.5 ± 11.1 years.
As expected, the sprinters were more muscular than the non-sprinters. However, more importantly, some muscles were disproportionately greater in the sprinters than in non-sprinters, even after adjusting for arbitrary body size units.
The chart below shows the details:
The importance of hip muscles for sprinting
As you can see from the chart above, all of the top 5 muscles are hip muscles (the semitendinosus, gracilis, tensor fasciae latae, rectus femoris, and sartorius).
In addition, 8 of the top 10 muscles are hip muscles (the semitendinosus, gracilis, tensor fasciae latae, rectus femoris, sartorius, obturator externus, gluteus maximus, vastus medialis, vastus intermedius, and piriformis).
And although by this point, the knee extensors are also accounted for, pretty much all of the hip musculature appears in the top 20 muscles (the semitendinosus, gracilis, tensor fasciae latae, rectus femoris, sartorius, obturator externus, gluteus maximus, vastus medialis, vastus intermedius, piriformis, tibialis posterior, adductor magnus, vastus lateralis, biceps femoris (long), biceps femoris (short), adductor longus, pectineus, quadratus femoris, adductor brevis, and semimembranosus).
Much of the bottom of the list is taken up by the ankle muscles, including both heads of the gastrocnemius, the soleus, the tibialis anterior, and the peroneals.
Why is there such an emphasis on hip muscles?
One way that we might explain the key role of the hips, the moderate role of the knees, and the lesser role of the ankle muscles in sprint running is a process known as “sequential kinetic linking.”
When a movement follows a sequential kinetic linking pattern, kinetic energy flows in a proximal-to-distal sequence. It starts at joints that are closer to the center of the body (which are proximal), and moves outwards to joints that are further from the center of the body (which are distal).
Indeed, Hunter et al. (2005) concluded that in the acceleration phase of sprinting, athletes do use a proximal-to-distal sequence in which peak extension velocity was first reached by the hip, then the knee and finally the ankle joint. Johnson & Buckley (2001) similarly concluded that there is first a generation of peak extensor power at the hip, followed by the knee, and then the ankle during the stance phase.
This would explain the key role of the hips, the moderate role of the knee extensors, and the much lesser role of the ankle musculature.
What did the researchers conclude?
The researchers concluded that elite sprinters tend to have disproportionally large hip extensors (hamstrings and gluteus maximus), hip flexors (sartorius, gracilis, and rectus femoris), knee flexors (semitendinosus), and knee extensors (vastus medialis, vastus intermedius) compared to non-sprinters. In contrast, the ankle muscles appear to be less important.
Now we know what muscles need to be prioritized to increase sprinting performance, stay tuned to find out about the best ways to train these muscles!