The force-velocity curve illustrates the inverse relationship between the force a muscle produces and the velocity at which it contracts. As the load an athlete moves increases, the speed at which they can move it decreases. Understanding this principle helps athletes enhance their power, which is the product of force and velocity. By training different points along this curve, individuals can improve their overall athletic performance.
Understanding the Force-Velocity Relationship
The force-velocity relationship governs all human movement. A clear example is comparing a powerlifter’s maximal deadlift to a baseball pitcher’s throw. The powerlifter applies a tremendous amount of force, but the barbell moves very slowly. In contrast, the pitcher generates incredible arm speed, but the force is applied to a very light baseball.
Maximum power output is not achieved at the extremes of the curve where either force or velocity is maximized. Instead, peak power is generated in the middle of the curve. This is the point where there is a balanced combination of substantial force and significant movement speed. Training to improve this quality involves lifting moderate loads at the highest possible velocity.
The Five Training Zones of the Curve
To effectively train for power, the force-velocity curve is divided into five distinct training zones. Each zone targets a different combination of force and velocity, allowing for specialized athletic development. Addressing each segment helps an athlete build a comprehensive physical foundation.
- Absolute Strength focuses on producing the maximum possible force, with movement speed as a secondary concern.
- Strength-Speed shifts the emphasis toward moving a heavy load with increasing velocity.
- Power represents the optimal balance of force and speed, where the highest power outputs are achieved.
- Speed-Strength prioritizes movement velocity while still using a light to moderate load.
- Absolute Speed involves moving with the highest possible velocity, with little to no external load.
Exercises for Each Training Zone
To target each of the five zones, specific exercises and loading parameters are used to produce the desired adaptations.
Absolute Strength
The goal is moving the heaviest possible load, above 90% of a one-repetition maximum (1RM). Common exercises include heavy back squats, deadlifts, and bench presses. The intent is maximal force production regardless of the speed of the lift.
Strength-Speed
The aim is to move a heavy load, between 80% and 90% of 1RM, as fast as possible. This zone helps bridge the gap between pure strength and power. Examples include heavy power cleans and loaded squat jumps, where the focus is on accelerating a significant weight.
Power
The Power zone is where peak power is developed, using loads that range from 30% to 80% of 1RM. The objective is to find the ideal combination of load and velocity. Exercises such as kettlebell swings, trap bar jumps, and hang power cleans are effective for this purpose.
Speed-Strength
The load is reduced to between 10% and 30% of 1RM, with the primary goal being maximal velocity. Box jumps, medicine ball throws, and unloaded vertical jumps are characteristic of this zone. These exercises train the body to generate force quickly against a light resistance.
Absolute Speed
This zone involves exercises with minimal to no external load, such as bodyweight or less than 10% 1RM. The focus is purely on achieving the highest possible movement velocity. Sprints, agility drills, and plyometric bounding are staples of this training zone.
Constructing a Balanced Training Program
A well-designed training program incorporates exercises from across the entire force-velocity curve to develop a balanced athlete. Neglecting one end of the spectrum can lead to deficiencies, such as an athlete who is strong but lacks the speed needed on the field. The goal is to strategically integrate different training stimuli.
One approach is to dedicate different training days to specific qualities. An athlete might have a “Max Strength Day” early in the week focusing on heavy compound lifts, and a “Max Velocity Day” later in the week centered on sprints and plyometrics. This method allows for focused effort and adequate recovery.
Another method is periodization, where the training focus shifts over time. During the off-season, an athlete might emphasize building a foundation of absolute strength. As the competitive season approaches, the focus would gradually shift towards power and speed-strength, translating that strength into sport-specific quickness.
Simple Assessment of Your Profile
To tailor a training program, it is useful to identify your own force-velocity profile. An athlete can be either “force-deficient” (strong but slow) or “velocity-deficient” (fast but weak). A simple self-assessment can help identify which end of the curve requires more attention.
One way to assess your profile is to compare your performance in a strength-dominant exercise with a velocity-dominant one. For instance, an athlete who can squat a high percentage of their body weight but has a poor vertical jump is likely force-dominant. This person would benefit from focusing on exercises in the speed-strength and absolute speed zones.
Conversely, an athlete who is quick and has a good vertical jump but struggles with heavy lifts is likely velocity-dominant. This athlete would need to spend more time on the force end of the curve. This simple comparison provides valuable direction for personalizing a training plan to address specific weaknesses.