Research
Mixed
Biomechanical factors such as muscle length and joint angles during compound exercises can lead to suboptimal activation of specific muscles, necessitating targeted isolation exercises to address these gaps.
Understand that squats and deadlifts don't work every muscle equally. For example, squats don't fully stretch or activate the rectus femoris or hamstrings. Add leg extensions and leg curls to your routine to ensure these muscles get adequate stimulus for growth.
GoodSupportsHIGH confidence
The activity of the vastus lateralis or medialis is considerably greater than the rectus femoris during squats, conceivably due to the bi-articular nature of the rectus femoris is not fully activated when the hip is flexed... The calf muscles are another region that can benefit from single-joint exercise... squatting does not allow a large range of motion of the ankle joint consequently minimizing involvement of the calf muscles during exercise performance.
Why this rating
Supported by EMG studies and longitudinal hypertrophy data cited in the paper.
Source
Resistance training exercise selection: efficiency, safety and comfort analysis method
Ewertton de Souza Bezerra et al. · Brazilian Journal of Kinanthropometry and Human Performance · 2021
DOI 10.1590/1980-0037.2021v23e82849
narrative_review
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Single-joint resistance exercises provide superior hypertrophy for specific muscle groups (e.g., rectus femoris, hamstrings, calves, biceps, triceps) compared to multi-joint exercises alone, necessitating their inclusion for optimal muscle development.Good
- Exercise selection must prioritize safety and comfort over maximal muscle activation to ensure long-term adherence and prevent injury, even if it means sacrificing some hypertrophic potential.Moderate
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