In the past it has been suggested that all you need to do to increase running, cycling, or swimming performance is to consistently put in more and more volume at your given sport. The thought process seems pretty sound, it does follow the theory of specificity. Practice does make perfect, right?
In fact, practice does increase a multitude of performance markers by simply allowing your body to adapt to a stimulus; this adaptation is from neuromuscular patterning that makes our bodies more efficient at whatever activity we do most often. The problem is that this same neuromuscular wiring system that helps us increase overall work capacity can start to work against our own systems safe guards to injury and we can start to develop significant movement imbalances.
*Warning: Science Content* On a bike, you can increase the load to a certain extent by learning how to maintain a faster pedal rate at a harder gear and this in turn will make you go faster. Running on the other hand is just about an increase in force velocity as your foot hits the ground and the loading remains constant. Swimming is again about force velocity against a constant, that being the water, which has been said to be a force of about 25 pounds of resistance. We can increase load to an extent with paddles by allowing us to grab more water with each stroke, but even that can only help to a certain extent.
What this means for the endurance athlete is that there can be significant health and performance benefits from embarking on a program that targets muscle imbalances, as well as force and velocity production through an increase in load as well as corrective mobility exercise.
Everyone to some extent has some sort of muscular imbalance that is due to either an activity they do on a regular basis or even from sitting for long periods of time. For those that are cyclist this is even more apparent. Those that are cyclists as well as having desk jobs are in a state of constant hip flexion. This constant state of hip flexion creates improper length-tension relationships and force-couple relationships within the muscles, especially those around the hip and midline.
The muscles on the anterior of the hip which are involved in hip flexion get shorter and those involved in hip extension on the posterior side tend to elongate. What this does is it takes those muscles out of there ideal tension range which decreases neuromuscular efficiency and firing, decreasing overall force production.
The same applies for the anterior side of the hip. When those hip flexors are shortened then the length-tension relationship on the other side of the curve is also minimized. By incorporating a strength training program that develops greater hip extension force production along with targeted mobility exercises we can help to sure up the muscular imbalances, placing the muscles in their optimal resting length so that they will be able to apply greater force during a bike ride or run.
Leg Strength and its Effect on Lactate Threshold
Numerous studies have been done to determine what an increase in leg strength will have on endurance performance. The main takeaway from these studies is that an increase in leg strength results in an increase in lactate threshold level that in turn results in greater glycogen sparing. What this means is that by increasing overall leg strength the rate of lactate accumulation in the blood is diminished allowing for greater time to exhaustion. In a study published by the Medical Science Sports Exercise Journal, which looked at the effect of strength training in conjunction with endurance training they found that “there were significant reductions in plasma lactate concentration at all relative exercise intensities ranging between 55 and 75% of peak VO2 training. The improved endurance performance was associated with a 12% increase in LT.” Another study published in the Exercise Sports Science Review looked at what physiological factors determining endurance performance ability and they found a significant indicator is how well the body utilizes glycogen. They took individuals with low lactate threshold values and individuals with high lactate threshold values and put them through a series of tests. What they found was that “the low LT group displayed more than a 2-fold higher rate of muscle glycogen use and blood lactate concentration, and as a result were able to exercise only one-half as long as the high LT group.”
An increase in overall strength capacity as well as correct length-tension relationships within the muscular fibers will help to increase overall force production as well as increase lactate threshold levels. The increase in lactate threshold levels will help to spare muscle glycogen allowing for greater time to exhaustion and therefore an increase in endurance performance.