Velocity

Defined simply it is a change in position over time with consideration to the direction of that change. In the fitness arena we could consider it to be how much distance you cover in a period of time, as well as in what direction you are moving. One interesting aspect regarding velocity is that it has an indirect relationship to force production. The faster you move, the less force you can produce.

A familiar concept in performance training is the force-velocity curve. This is a visual representation of the indirect relationship between the two variables. As one goes up, the other goes down. One example to consider would be an Olympic weightlifter. Movements like the snatch require a delicate balance between force production and speed. As the lifter increases the velocity of the movement, the ability to move heavier weights declines. Another example would be the 100-meter sprint. World-class sprinters are unique in that they can produce an immense amount of force in a split second. The reason most of us never make it to that level is because as we try to move faster, our ability to push in to the ground diminishes. Force production declines, and we fall behind in the race.

This can also apply to daily activities. Most of us are stretched thin for time during a typical day. There are things to do and not enough time to do them. We attempt to move faster in order to get our stuff done, however that comes at the cost of producing force. In general terms, we sacrifice some strength to cover more ground. As time goes by this becomes our default strategy, we focalize where we generate force and non-uniform pressures develop. If this goes on for long enough, we may develop a painful situation, one in which forces have not been attenuated evenly throughout the system.

A frequent conversation I have with clients revolves around this topic. It may be that during a training session exercise transitions need to slow down, or rest breaks between sets need to go up. It may be a matter of taking some time in the morning to slow down and perform a few activities that promote the ability to absorb forces more uniformly. Often if we can learn to fluctuate between velocity and force production, things feel much better.

Austin Ulrich, Physical Therapist