Power is often misused with regards to athletic performance; coaches, trainers and fans often talk about how ‘powerful’ certain athletes are. Certain sports such as baseball, football and weightlifting are even considered “power” sports. What does this mean exactly?
This week, we will clarify the distinction between ‘power’ and ‘peak power’ and outline why strength training is so crucial in the development of ‘peak power’.
Power vs. Peak Power
Power is defined as the rate of ‘doing work’ and can be expressed as:
Power = work/time.
Power is present in almost all movements except for isometric actions. Power actions can therefore range from long-lasting movements like running to short-lasting movements like throwing.
When referring to short-lasting movements, the term peak power must be used. Peak power is more instantaneous and although it can be expressed in the same manner as power (above), as it relates to explosive movements, it usually looks like this:
Power = Force x Velocity.
Throwing, kicking, striking, quick bursts of speed and change-of-direction.
Peak Power and the F-V Curve
Last week’s post outlined the five segments that make up the force-velocity curve. Peak power is located somewhere between force and velocity and if you look at Figure 1, you’ll notice that the 1RM range that maximizes peak power is quite large. Why is this the case?
3 Loading Parameters for Peak Power:
1. Training experience of the athlete
2. Training phase of the athlete during the yearly plan
3. The nature of the exercise → upper body vs. lower body, single-joint vs. multi-joint, traditional vs. explosive
Why Lifting Weights Leads to Improved ‘Peak Power’ Production
Although a jump elicits a higher peak power output then a heavy squat, the latter is a prerequisite for the former. There are several underlying mechanisms that contribute to an increased ability to produce peak power and they can be grouped as either neural factors or muscular factors. Let’s take a look:
1. The recruitment of high threshold motor units (M-Us):
These M-Us are composed of type 2 fibers which are associated with the generation of max power production.
2. Improved efficiency to recruit larger M-Us
The ‘Size Principle’ states that when performing any movement, small M-Us are recruited first, followed by larger M-Us. Research suggests that trained athletes are able to bypass the activation of small M-Us and go directly to larger M-Us (remember, these are CRITICAL for peak/instantaneous power production).
3. Increased firing frequency:
The nervous system becomes more ‘active’, allowing for max RFD (rate of force development) to occur. It’s important to note that peak power is closely related to max RFD (more on RFD in a later post).
4. Greater synchronization of M-Us:
M-Us are effectively working more efficiently and therefore produce ‘smoother’ movements (think of an NBA superstar rising up for a dunk).
1. Muscle Cross-Sectional Area (CSA):
CSA just means the ‘size’ of the muscle. When a muscle gets bigger, it usually gets stronger. And remember, strength is a prerequisite for peak power production. Too much mass however, can limit your range of motion and cam slow movements down; the result, diminished power production.
2. Fiber Type:
Type 2 fibers (aka fast-twitch fibers) are associated with powerful/explosive movements. The amount of type 2 fibers are genetically predetermined but there’s still hope; strength training predominantly recruits type 2 fibers, increasing their size and the % usage.
We’ll look at different approaches to optimizing peak power production through the manipulation of exercises, loading schemes along with other program variables.
1. Kawamori and Haff 2004. The optimal training load for the development of muscular power. Journal of Strength & Cond Research.
2. Knudson 2009. Correcting the use of the term “power” in the strength and conditioning literature. Journal of Strength & Conditioning Research.