What are they?
ForceHooks are a transportable dynamometer that may be secured to a weight room rack as proven under. The opposite finish of the machine is modular, presently that includes a watch bolt, a hook designed to safe a barbell, and an open attachment for handheld resistance measurements.
The power to safe between a barbell and a rack is groundbreaking in that the machine can be utilized to measure any barbell isometric train. This might make for a transportable setup for the Isometric Mid-Thigh Pull (IMTP), like what we use in our energy evaluation course of. Nevertheless, it may very well be accomplished with out the necessity for pressure plates or checks of which the output can be troublesome to measure, even with pressure plates (i.e., an isometric row).
How correct are they?
Earlier than implementing the ForceHooks with our athletes in any capability, we would have liked to validate the machine’s accuracy. Utilizing our moveable dual-force plates from ForceDecks, we have been capable of arrange an IMTP rig as proven under.
To scale back potential error that would happen from the setup of the rig and never the gadgets, we positioned a plywood layer beneath the plates to account for the slight give of the rubber health club flooring. We additionally opted for a stiff 29mm energy bar rather than a typical barbell to attenuate the bend of the bar through the pull.
With a pattern measurement of 65 trials, we in contrast the total sign pressure traces from the ForceHooks to the pressure plates after which calculated the distinction between the 2 alerts at every pattern.
To get a greater thought of how the magnitude of the pull impacts the error of the hooks we additionally checked out a Bland Altman plot which illustrates how the error modifications throughout various magnitudes of a measure. This tells us if the error in measurement modifications when a trial exhibits excessive vs. common or low forces.
Here’s what we discovered:
- Imply error in max pressure studying: -28.97 N (FH on common reads about -29 N decrease than pressure decks)
- Imply absolute error when pressure is above 75% of max: 66.1 N (2.55% error)
- Imply absolute error throughout the entire recording: 93.0 N (3.62% error)
- Common correlation between the alerts: r = .9895 (r^2 = 0.979)
- Instance pressure hint alignment of 1 trial
With a mean max pressure error of -28.97 N (~1%) and an r^2 for the total pressure hint of 0.979, we really feel very assured implementing the ForceHooks. Their versatility will open up new isometric evaluation choices that beforehand weren’t possible, together with doubtlessly increasing our energy evaluation to incorporate higher physique pressure manufacturing.
Written by Connor White