# Biomechanical comparison of two squatting protocols in adolescents and young adults with femoracetabular impingement syndrome

## TL;DR

This study compares two squatting techniques in adolescents and young adults with hip issues, finding that a traditional squat leads to deeper squats and different biomechanics.

## Contribution

The study introduces a novel comparison of traditional and held squat techniques in individuals with femoracetabular impingement syndrome.

## Key findings

- Participants squatted deeper with the traditional squat compared to the squat with a hold.
- Greater hip, knee, and ankle flexion was observed in the traditional squat.
- Peak power and moment generation at the knee were higher in the traditional squat.

## Abstract

Squatting is an important activity of daily living which can be particularly useful in the management of Femoroacetabular Impingement Syndrome (FAIS). However, double-leg squat protocols can vary significantly, potentially impacting biomechanical outcomes. A squat with a “hold” before the ascent phase represents one variation which increases muscular endurance demands and may elucidate such impacts. The purpose of this study was to identify biomechanical differences between a traditional squat (TSquat) and squat with a hold (HSquat) in adolescents and young adults with pre-operative FAIS.

Participants (N = 46; 35 females; 16.5 ± 1.7 years) undergoing primary unilateral hip preservation surgery for FAIS completed two squat types assessed via 3D motion analysis. The TSquat was performed with descent immediately followed by ascent. The HSquat included a three second pause at participants’ lowest comfortable position. Joint range of motion, moments, powers, and squat depth in participants’ pre-operative limb were compared between each technique.

Participants squatted lower in the TSquat than the HSquat (42.6% ± 12.8% vs. 36.0% ± 13.0%, p < 0.001). Maximum hip, knee, and ankle flexion were greater in the TSquat (mean difference: 4.2 ± 0.7°, 10.2 ± 1.2°, 1.4 ± 0.1°, respectively; p < 0.05). Peak sagittal moment at the hip/knee (mean difference: 0.10 ± 0.05 Nm/kg, 0.09 ± 0.08 Nm/kg, respectively; p < 0.001) and peak power generation at the knee (mean difference: 0.40 ± 0.16 W/kg; p = 0.001) were also greater in the TSquat.

Participants with FAIS squatted to a shallower depth during the HSquat compared to the TSquat and displayed altered biomechanics, accordingly. Given these findings, greater standardization of squatting techniques is warranted as technique variations may affect outcomes, and researchers must consider potential adjustments made by those with FAIS in their natural squat movement.