In general, endurance athletes put resistance training on the back burner.
It makes sense at first glance. The SAID principle, Specific Adaptation to Imposed Demands, suggests that endurance athletes should prioritize their activity over resistance training.
Although that may be true to some extent, any runner that has ever been injured due to an overuse injury knows the importance of resistance training to avoid muscle imbalances. With that said, lifting heavy seems a bit counter intuitive to an optimal resistance training approach.
Misconceptions of lifting heavy
Lifting heavy can’t improve endurance
Although lifting heavy doesn’t explicitly aim to improve endurance performance, something is to be said for increasing the load your musculoskeletal system can take.
The endurance athletes should lift heavy for the same reasons we do interval training.
Similar to how a hard interval trains our body to handle low intensity running easier, lifting heavy trains our body to easily handle the muscle tension from endurance training.
On the flip side, lifting light weight for high reps does focus on muscular endurance. The only problem with that is your regular training is making the muscles you use for running fatigue resistant. Lifting for high reps does not do much in the way of diversifying your training.
Like mentioned above, focusing on strength allows your muscles to develop the ability to handle more acute stress, thus making the stress of endurance training that much easier to handle.
Lifting heavy will make me too big
It is important to differentiate lifting for strength vs. lifting for size. Strength training won’t necessarily make you bigger assuming you are lifting as a cross training regimen to supplement your endurance race training.
Muscular hypertrophy isn’t as easy health magazines make us believe. It takes a focused approach and a science proven regimen of breaking down muscle and allowing for recovery. A quick, twice a week strength training program most likely won’t make you build unwanted muscle bulk.
Although lifting heavy weight requires a set of skills that running doesn’t, it is essential to add to your tool belt if you are looking to optimize your endurance training.
Keep in mind that you should seek the use of spotters and/or trainers and use a lot of caution when starting a new strength training program.