Comparison of Kinetic Variables and Muscle Activity During a Squat vs. a Box Squat.

[Darryl Shaw]

Comparison of Kinetic Variables and Muscle Activity During a Squat vs. a Box Squat.

Abstract

McBride, JM, Skinner, JW, Schafer, PC, Haines, TL, and Kirby, TJ. Comparison of kinetic variables and muscle activity during a squat vs. a box squat. J Strength Cond Res 24(12): 3195-3199, 2010-

The purpose of this investigation was to determine if there was a difference in kinetic variables and muscle activity when comparing a squat to a box squat. A box squat removes the stretch-shortening cycle component from the squat, and thus, the possible influence of the box squat on concentric phase performance is of interest. Eight resistance trained men (Height: 179.61 ± 13.43 cm; Body Mass: 107.65 ± 29.79 kg; Age: 24.77 ± 3.22 years; 1 repetition maximum [1RM]: 200.11 ± 58.91 kg) performed 1 repetition of squats and box squats using 60, 70, and 80% of their 1RM in a randomized fashion. Subjects completed the movement while standing on a force plate and with 2 linear position transducers attached to the bar. Force and velocity were used to calculate power. Peak force and peak power were determined from the force-time and power-time curves during the concentric phase of the lift. Muscle activity (electromyography) was recorded from the vastus lateralis, vastus medialis, biceps femoris, and longissimus. Results indicate that peak force and peak power are similar between the squat and box squat. However, during the 70% of 1RM trials, the squat resulted in a significantly lower peak force in comparison to the box squat (squat = 3,269 ± 573 N, box squat = 3,364 ± 575 N). In addition, during the 80% of 1RM trials, the squat resulted in significantly lower peak power in comparison to the box squat (squat = 2,050 ± 486 W, box squat = 2,197 ± 544 W). Muscle activity was generally higher during the squat in comparison to the box squat. In conclusion, minimal differences were observed in kinetic variables and muscle activity between the squat and box squat. Removing the stretch-shortening cycle during the squat (using a box) appears to have limited negative consequences on performance.

http://journals.lww.com/nsca-jscr/Fu..._Muscle.1.aspx

[Matt Thomas]

Very interesting.

"Removing the stretch-shortening cycle during the squat (using a box) appears to have limited negative consequences on performance."

Do you think this could also read "removing the stretch shortening cycle appears to have limited added benefit?"

[Blair Lowe]

Well, the stretch-shorten cycle merely lets you lift a weight or force a bit more than you could do without. Effectively, it's a little trick to help out.

With many movements, it just becomes way more involved to take it or set it up. For instance like concentric squats.

[Spencer Mackay]

In the interests of athletic development, you could probably do mainly box squats if you continued to incorporate plyometric work into your program to make use of the SSC.

However, I'm a traditionalist and I think there are other benefits of full squats.

[Greg Everett]

"However, during the 70% of 1RM trials, the squat resulted in a significantly lower peak force in comparison to the box squat (squat = 3,269 ± 573 N, box squat = 3,364 ± 575 N). In addition, during the 80% of 1RM trials, the squat resulted in significantly lower peak power in comparison to the box squat (squat = 2,050 ± 486 W, box squat = 2,197 ± 544 W). Muscle activity was generally higher during the squat in comparison to the box squat."

This is the part that's interesting to me. I think it's pretty simply explained - the momentum from the SSC is able to carry the lifter through the ROM faster and with less concentric muscular force. Although the last sentence above is confusing - presumably in the complete study they define what all they considered "muscle activity" since it must be more than peak force.

I would be more interested in seeing a similar study comparing a full-depth Olympic style pause/stop squat vs. a box squat. I think you would see the higher peak forces that they found in the box squat, but an even higher total "muscle activity" than the squat with SSC.