Have you noticed on your training plans you’ll have intensity on one, rest on the other, XT on certain days? When you add strength training (whether you’re an endurance or short distance athlete) it’s imperative to add a variety of weight lifting, cross-training, etc. Ensuring you’re not adding stress to the “over-trained” running muscles so that you’re able to recognize when to “back off” from training when your muscles feel excessively fatigued or sore.
Muscles are damaged on hard training days, and they heal and get stronger on the following slower recovery day. Lifting weights (excessively or aggressively) on a recovery day prevents your muscles from healing. Extensive data show that lifting weights damages muscle fibers for at least a day afterwards, so that the involved muscles are weaker and would interfere with any attempted intense endurance workouts on the next day (Sports Med, Nov 2017;47(11):2187-2200). For at least a day after lifting weights, athletes are at high risk for tearing muscle fibers if they attempt intense endurance workouts.
Research Supports Strength Training
In one study, 19 well-trained female duathletes were assigned to either:
- run and cycle with an added strength training program, or
- just run and cycle.
The strength training program included four lower body exercises, three times each, twice a week for 11 weeks. The added strength training improved their running and cycling performance done after strenuous exercise, but not after resting (Physiol Rep, Mar 2017;5(5)). This is just the latest of many conflicting studies that show either improvement or no improvement when strength training is added to an endurance sport training program.
A review of many scientific articles shows that runners and bicycle racers can run and cycle faster with added strength training (Scand J Med Sci Sports, Oct 2010;20 Suppl 2:39-47) because it makes them stronger (J Strength Cond Res, 2013;27(9): 2433–2443), so that they can run and cycle more efficiently with less effort (Med Sci Sports Exerc, 2008;40(6): 1087–1092). Other research shows that adding strength training to an endurance program can make muscles larger and stronger (Sports Med, Aug 2016;46(8):1029-39). However, the improvement in racing performance with added weightlifting is small, and sometimes nonexistent, because lifting weights does not improve VO2max (the ability to take in and use oxygen). The limiting factor for how fast an endurance athlete can run or cycle is the time it takes to move oxygen into muscles, and that is improved only by training that involves becoming short of breath (Med Sci Sports Exerc, 2002;34(8):1351–1359).