Effect of Squat Depth and Load on Muscular Effort

Effect of Squat Depth and Load on Muscular Effort

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The squat is a popular dry-land exercise for swimming. This is likely due to the numerous muscles involved and the common belief this motion mimics a flip turn (despite contradictory research). However, the effect the depth and load on the squat are unknown.

Muscle force is hard to measure, therefore motion analysis techniques combined with the equations to solve for the net joint moment (NJM) acting on a segment are used to determine the mechanical effort required.

The purpose of this study was to investigate the effects of barbell load and squat depth on hip extensor, knee extensor, and plantar-flexor relative maximal effort (RME) during squatting exercise.

What was done

Ten strength-trained women performed three sessions:
1. back squat 1 RM test
2. motion analysis of back squat exercise
3. maximum isometric strength testing
Prior to the third session, maximum voluntary isometric contractions were performed to determine the maximum strength of the participant's hip extensors, knee extensors, and ankle plantar-flexors.

Results

A significant interaction between barbell load and squat depth on hip extensor, knee extensor, and ankle plantar-flexor RME was found. For ankle plantar-flexor RME, load had a greater effect than depth. Barbell load had the largest effect on the knee extensors. Hip extensor noted the largest alteration with squat depth, but squat load noted similar increases.

Discussion

The key findings were that barbell load had a more prominent effect on the ankle plantar- flexors, whereas the barbell depth had a larger influence on the knee extensors. The hip extensors had a similar increase with load and depth.

Practical Implication

Squatting depth and load alter the involvement of the hip and knee extensors and ankle plantar-flexors. Therefore, these differences must be considered when determining load and depth for each swimmer. For example, a swimmer with knee pain likely needs improvement in hip extensor, not knee extensor strength, and a heavyweight with low depth are indicated.

Related Reading

SQUAT STRENGTH NOT THAT IMPORTANT FOR VERTICAL JUMPING
FACTORS FOR TRAINING EXPLOSIVE POWER
DEPTH JUMPING AND WEIGHT TRAINING EFFECTS
Should Swimmers Squat with a Heel Lift?
Back squat to improve swimming

 

Reference: 

  1. Bryanton MA, Kennedy MD, Carey JP, Chiu LZ.Effect of Squat Depth and Barbell Load on Relative Muscular Effort in Squatting. J Strength Cond Res. 2012 Jul 12. [Epub ahead of print]

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