The Correlation of Speed and Strength
The Correlation of Strength and Speed
It is becoming more and more common to see performance coaches try and equate strength lifts to speed. Some have chosen the deadlift, back squat, reverse lunge, or even a combination of a lower body lift and an upper body lift such as the pull-up. These methods are not without merit. There is a value to being able to identify or even predict the speed capabilities of an athlete without having to need the field space or tapering the program to allow them to sprint at max velocity each time. In our minds, we also wanted to identify when an athlete was “strong enough.” In our minds, this would help us not only with athlete programming, but more so with athlete buy-in. It seems most often the strongest athletes show the greatest resistance to lowering the total amount of lifting volume. We figured if we could tangibly show them their weakness in this regard, they would have less resistance to change.
We started looking at this question a while ago to figure out why it hasn’t been able to be done accurately before. Our first step was to look at the denominator between speed (specifically acceleration) and strength, which was force. The first glaring weakness we saw in the previous attempts to equate strength to speed, was the inability to account for the rate at which the force is applied. Previous attempts went off of weight lifted relative to bodyweight, but force has a speed component as well. The equation for force is Mass x Acceleration, which means that it is possible to technically move 405lbs with less force than 315lbs depending on the speed at which the weight is moved. So right off the bat, we eliminated any single lift as just weight lifted by itself.
As we discussed this topic further, as a staff, we ran into another possible issue. We realized that each athlete is going to express athletic qualities differently. For example, fascia driven athletes with more type 2 muscle fibers might not need a great amount of strength to be fast. In fact, they may only need a base level of strength to remain healthy, but too much hypertrophy and strength style training may actually take away what makes them great. The other possible issue, using a similar example is that - is there ever such a thing as too much strength? We consider strength to be the ceiling of force production in athletics. Theoretically, if an athlete’s technique was on point and they produced force at a high rate, then the only way to increase their speed would be to get stronger, so why would we want to cap that?
With these in mind, we came up with what we believe to be a better way of looking at this problem, and that is through ratios. We now prefer to look at the type of force the athlete is producing and how. This can be done simply by testing static vs. countermovement jumps, which will give you an idea of the athlete's force to velocity ratios. Our preferred method is to identify these traits through force plate testing. There we can see what kind of eccentric force (anterior strength primarily), concentric force (core stiffness and contractile strength), and the fluidity of the concentric force being produced by relating it to the time taken to distribute it. Force plate testing is another article in itself, but by looking at these numbers, we can tell when an athlete is “strong enough,” but then we can also tell when he needs to go back and raise his strength ceiling to allow for more speed and power. More importantly, we can see exactly what type of athlete he is, versus the type he needs to become.
There may be a coach that is smarter than us that comes along with a simpler way to correlate strength to speed, but until that time, we maintain that to get the most in-depth and accurate look at whether an athlete is “strong enough,” ratios are the way to go.
Sources
Mizuguchi, Satoshi. “Net Impulse and Net Impulse Characteristics in Vertical Jumping.” Dc.etsu.edu, East Tennessee State University, Aug. 2012, dc.etsu.edu/cgi/viewcontent.cgi?referer=https://www.bing.com/&httpsredir=1&article=2652&context=etd.
Richmond, Jeremy. “Newtonian Model of an Elite Sprinter: How Much Force Do Athletes Need to Produce Each Step to Be World Class?” Http://Elitetrack.com, University of Sydney, 2008, elitetrack.com/article_files/newtonian-sprinting.pdf.