While many NFL athletes lift at their heaviest during the off-season, due to the fact that they don’t have a packed schedule of football games to maintain, experts like Natalie Kollars, a strength and conditioning coach and founder of Fortis, know that proper strength and conditioning also requires explosiveness and speed. To that end, many athletes also focus on moderate loads, and for good reason.

“Focus on moderate load to maximize power and rate of force development,” explains Kollars in a recent Instagram post in which she worked with Seattle Seahawks running back Deejay Dallas.” This performance specialist, with an MSc in Exercise Physiology and Strength & Conditioning aims to “drive intent” among her football playing clients, rather than simply overload them with barbells. It’s all about the force-velocity relationship.

The Force-Velocity Relationship

The relationship between the amount of force that a muscle can produce is intrinsically linked to the speed of the muscle contraction. So, as the load increases, the speed of movement will decrease. Training with moderate loads makes sense because football requires athletes to exhibit explosive power in various movements such as sprinting, jumping, and changing direction rapidly. Training with moderate loads can closely mimic the demands of these movements, making the training more specific to the requirements of sports such as football. The definition of a “moderate load” is individual to each player’s strength level, but it will typically be a weight that can be performed 8 – 12 times while maintaining good form.

“The force velocity curve is a tool I refer to when programming for my athletes,” Kollars says. Creating the desired adaptation is all about prescribing the correct stimulus. If the goal is to increase an athletes power capabilities, we need to prescribe a load that falls in the middle of the curve.”

Moderate loads allow athletes to move the weight with a moderate speed, striking a balance between force and velocity. This is ideal for power development, as power is the product of force and velocity. Training with moderate loads enables athletes to generate force while still moving the weight at a relatively high speed, promoting power production. Moderate load training also engages both the fast-twitch and slow-twitch muscle fibers. Fast-twitch fibers are crucial for explosive movements, and by targeting them with moderate loads, athletes can enhance their neuromuscular adaptations, something that is necessary for making gains with explosive power and speed.

Compared to training with heavy loads, which is also thought to improve speed and power, moderate load training puts less stress on the joints and connective tissues. This reduced stress lowers the risk of injuries, allowing highly paid athletes like NFL players to consistently engage in training without compromising their overall health and performance, meaning that when the season begins, a player should be ready to go.