Words: Sarah Hunter

Doesn’t strength training make you heavier and bulk up too much for riding?

This is a common question I get from many endurance athletes and mountain bikers. They are worried that by hitting the gym they will end up looking like Arnie and therefore this might impact their power to weight ratio. 
In the strength and conditioning world there is an effect called the interference phenomenon. This basically means that adaption effects of cardio (ie riding your bike) interferes with the hypertrophy (increase in muscle size) effects of lifting weights. Typically, this interference effect is only one way, so hypertrophy is compromised by endurance exercise, but endurance performance is enhanced by strength and power training. This is not so good for hardcore gym goers whose only aim is to bulk up, and this is why you don’t see any weightlifters doing much, if any, cardio. However, this effect is a positive for us; we can reap the rewards of strength training without getting bulky.
Pre-2000, the athletic community believed that strength was mainly determined by the size of the muscle. It has now been shown in multiple studies since 2000 that the neural system plays the primary role in determining strength. You may ask…How does this affect me? Since a muscle consists of motor units and the motor units activates the muscle fibers, then the more motor units you can use the more muscle you can utilise.

The primary effects of strength training will therefore be the ability of your body to recruit more motor units and recruit these motor units faster.  More motor units firing means more force created by the muscle and more power to the pedal stroke, all without getting bulky.
The take away

Cycling endurance can be improved with a lower volume, heavier weights program. You won’t gain muscle or increase body weight, but your performance will improve. Endurance athletes will benefit from strength training because it will offset the catabolic nature of prolonged endurance exercise. (Catabolic means the breaking down of lean muscle tissue to fuel the body).