Long distance runners have known for a long time that they do not need to have the muscular physique of sprinters or bodybuilding. Swelling muscles does not improve performance; it makes you bigger and heavier while these runners want to be thin and light.
However, leg exercises without weights training is still very common and recommended for distance runners, because it can increase power and possibly reduce injuries. Runners do a lot of exercises for the quads, hoping to reduce knee problems. Thus, many runners have quadriceps muscles that are 30% to 40% stronger than their hamstrings (under the thighs).
This could be another example of the “having too many muscles” error, according to this new study that compared the ratio of hamstring strength to quadriceps strength in highly trained or amateur long distance runners. . The group of highly trained athletes had lower absolute strength in both cases.
More important according to the researchers: the highly trained riders had a quadriceps hamstring ratio of about 1: 1 (equal) and a much higher racing economy than amateur runners.
Conclusion: The performance of the race on long distance events may well be associated with greater hamstring strength compared to quadriceps strength, and not with absolute muscle strength.
The study compared 7 highly trained riders with 11 amateur riders. The first group ran an average of 100 km per week; the second group ran about 35 km a week. Both groups had an average age of 25 years. All the runners have been tested on their running economy and their ratio of hamstring strength on the quadriceps.
The less trained runners actually had stronger muscles. However, this was correlated with a race economy that was lower. The top runners had weaker muscles, but a ratio of quadriceps strength to more balanced hamstring strength, and a much better race economy. That is, they used less oxygen at a given rate.
The strides of running require the two groups of muscles to contract concentrically and eccentrically. Actions are therefore contrary; while the quadriceps are lying down, the hamstrings are shortened and vice versa. In a well-oiled machine, the two groups of muscles function more efficiently together when their strength is the same.
The study article states that since running is basically a series of small horizontal jumps that require a very effective expander device, the researchers suggest that runners should add weight training for the hamstrings that involve these horizontal movements.
Runners should do exercises that mimic running when they add some weight training or acceleration exercises. For example, jumping or running on steep climbs, running quickly downhill or doing horizontal jumping maneuvers like jumping several times and as far as possible on one leg. These exercises should be combined with a more specific weight training that targets the hamstrings.