Exercise-induced muscle damage (EIMD) is usually caused by new or unaccustomed exercise, particularly if the exercise involves a large amount of muscle lengthening contractions, and results, among other things, in a temporary decrease in muscle force production and increased muscle soreness and swelling. But did you know that EIMD can be used to positive effect? Learn how pre-conditioning could improve your time.
Endurance runners improve performance by doing endurance running, right? Well, this isn’t entirely true. Sport and exercise experts say that there’s increasing evidence that resistance training, such as squats, can improve endurance performance, and different studies have shown that a 6- to 12-week lower limb resistance training programme can improve time-trial performance and running economy. Experts explain that doing unaccustomed resistance exercise can lead to exercise-induced muscle damage (EIMD).
Adverse effects include reduced muscle strength, delayed onset muscle soreness (DOMS), muscle swelling, muscle stiffness, and decreased range of motion. These symptoms are most severe around 24 to 48 hours after muscle-damaging exercise and affect endurance performance. Heart rate, breathing rate, oxygen consumption, and perceived effort are increased during fixed-intensity running when experiencing EIMD. Running time trial performance is also impaired; studies showed that the time to complete a 3km running time trial is increased by up to 9% as a result of EIMD.
However, recent studies show that EIMD can be used to positive effect by runners. It appears that after an initial bout of EIMD, the muscle adapts, whereby symptoms and the negative effects of EIMD on endurance performance are reduced. These findings are discussed in a study published in the European Journal of Applied Physiology under the title “Lower-volume muscle-damaging exercise protects against high-volume muscle-damaging exercise and the detrimental effects on endurance performance.”
Squats. Fourteen days later the process was repeated, except that all participants completed high-volume squats, followed 48 hours later by a second bout of fixed-intensity running and the 3km running time trial.
Two important findings were:
- Both high-volume and low-volume squatting led to EIMD after the first bout of exercise.
- However, EIMD symptoms were reduced in all participants after the second bout of muscle-damaging exercise.
This proves that lower-volume resistance exercise protects muscle against high-volume muscle-damaging exercise. The negative effects of EIMD on running time-trial time were reduced for both groups after the second bout of squatting. Researchers stated, it’s likely that the initial bout strengthened muscle fibre integrity, which consequently decreased muscle soreness and maintained running time trial performance after the second bout.
The study showed that the first and second bouts of lower limb resistance exercise don’t have to be identical for there to be a protective adaptation. A relatively mild bout of lower limb resistance exercise protects against EIMD following a heavier bout of lower limb resistance exercise.
What does the results imply?
Runners who are thinking about lower limb resistance exercise to improve endurance performance or overall health and well-being should perform the first bout of a low volume to pre-condition the muscle and protect it against further muscle damage following the second bout of resistance exercise.
Sport researchers plan subsequent studies. They plan to investigate older endurance athletes. As people age, the muscle damage response is more severe and it takes longer to recover. A lot of research on the effects of EIMD on endurance performance has been concentrated on younger athletes. But now researchers are interested in how would more older-aged athletes competing in endurance events respond to and recover from muscle-damaging exercise.