Effect of foot placement on muscle activation during the leg press

Abstract

<h2>Abstract</h2> <p>The leg press is a widely used machine-based lower-body exercise, and foot placement — including vertical position on the footplate and horizontal stance width — is a commonly manipulated variable in training practice. Despite widespread usage variation, the differential effects of foot placement on <a href="/terms/muscle-activation/" class="term-link" data-slug="muscle-activation" title="muscle activation">muscle activation</a> patterns across the quadriceps, hamstrings, and gluteus maximus have not been comprehensively characterized. This study examined <a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a> activity of the vastus lateralis, vastus medialis, rectus femoris, biceps femoris, and gluteus maximus across four foot placement conditions: high narrow, high wide, low narrow, and low wide. Twenty-four resistance-trained participants performed each condition at 70% of their standard leg press <a href="/terms/one-repetition-maximum/" class="term-link" data-slug="one-repetition-maximum" title="1RM">1RM</a>. High foot placement produced significantly greater biceps femoris and gluteus maximus activation, while low placement produced greater vastus lateralis and rectus femoris activation. Stance width independently influenced gluteus maximus and adductor recruitment, with wide stance elevating both. These findings provide a mechanistic basis for strategic foot placement manipulation during leg press training to emphasize different lower-body muscle groups.</p>

Introduction

<h2>Introduction</h2> <p>The leg press is among the most commonly performed machine-based lower-body exercises in commercial gym settings. Its fixed movement path, bilateral loading, and seated position make it a practical alternative or complement to free-weight squats, particularly for individuals learning lower-body training, recovering from injury, or seeking to isolate the quadriceps without the spinal loading demands of barbell squats [1]. The leg press recruits a similar constellation of muscles as the squat — quadriceps, hamstrings, gluteus maximus, and calves — but the machine-guided movement path reduces the technical skill demands and allows substantially different foot placement configurations to be explored.</p> <p>Foot placement on the leg press footplate is one of the most commonly discussed variables in training literature and coaching practice. Two primary dimensions of foot placement are typically manipulated: the vertical position on the footplate (high versus low) and the horizontal stance width (narrow versus wide). These adjustments are believed to shift the balance of muscular contribution between the quadriceps and the posterior chain (hamstrings and gluteus maximus), as well as between the lateral and medial quadriceps [2].</p> <p>The biomechanical rationale for these effects relates to changes in knee and hip joint angles and their associated moment arms at the point of peak effort. High foot placement is theorized to increase hip flexion range and knee angle at the bottom position, creating conditions where the gluteus maximus and hamstrings contribute more as hip extensors throughout the <a href="/terms/range-of-motion/" class="term-link" data-slug="range-of-motion" title="range of motion">range of motion</a>. Low foot placement reduces hip involvement by limiting hip flexion range and places a greater proportion of the pressing effort on knee extension, thereby increasing quadriceps demand [3].</p> <p>Similarly, wide stance is associated with increased hip abduction, which should theoretically engage the gluteus maximus and hip adductors to a greater degree. The gluteus maximus contributes to both hip extension and hip external rotation, and its mechanical advantage may be enhanced by wider stance positions that place the femur in greater abduction [4].</p> <p>Despite the widespread clinical and practical application of foot placement variation in leg press training, controlled <a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a> studies directly comparing multiple placement conditions are relatively sparse, and existing studies have often examined only one dimension (either height or width) in isolation. This study addresses this gap through a 2x2 factorial comparison of foot height (high vs. low) and width (wide vs. narrow).</p>

Methods

<h2>Methods</h2> <p><strong>Participants</strong></p> <p>Twenty-four resistance-trained adults (14 men, 10 women; mean age 24.1 ± 3.9 years; mean leg press <a href="/terms/one-repetition-maximum/" class="term-link" data-slug="one-repetition-maximum" title="1RM">1RM</a> 152.7 ± 38.4 kg) participated. All participants had at least 6 months of regular leg press training experience. Exclusion criteria included any current knee, hip, or lumbar pathology that might be exacerbated by leg press loading. Written informed consent was obtained.</p> <p><strong>Exercise Protocol</strong></p> <p>A 45-degree angle leg press machine was used for all conditions. Four foot placement conditions were tested in randomized counterbalanced order:</p> <table> <thead> <tr> <th>Condition</th> <th>Vertical Position</th> <th>Horizontal Width</th> </tr> </thead> <tbody> <tr> <td>High Narrow</td> <td>Upper third of footplate</td> <td>Hip-width apart</td> </tr> <tr> <td>High Wide</td> <td>Upper third of footplate</td> <td>Approximately 1.5x hip width</td> </tr> <tr> <td>Low Narrow</td> <td>Lower third of footplate</td> <td>Hip-width apart</td> </tr> <tr> <td>Low Wide</td> <td>Lower third of footplate</td> <td>Approximately 1.5x hip width</td> </tr> </tbody> </table> <p>Foot angle was maintained at 15–20 degrees of external rotation across all conditions. All conditions were performed at 70% of the participant's leg press 1RM established during a preliminary session. Each condition involved 3 repetitions at a standardized tempo (3-second descent, 1-second pause, 2-second ascent). <a href="/terms/range-of-motion/" class="term-link" data-slug="range-of-motion" title="Range of motion">Range of motion</a> was matched at approximately 90 degrees of knee flexion at the bottom and full extension at the top (without locking out). Rest between conditions was 4 minutes.</p> <p><strong><a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a> Data Collection</strong></p> <p>Surface electrodes were placed on the vastus lateralis (midpoint of the muscle belly at approximately 60% of the distance between the greater trochanter and lateral knee), vastus medialis oblique (approximately 4 cm proximal to the upper patella, directed along the VMO fiber angle), rectus femoris (50% of the distance from the ASIS to the patella), biceps femoris (proximal to the lateral knee, midpoint of the posterior thigh), and gluteus maximus (per SENIAM guidelines, 50% of the distance between the PSIS and the greater trochanter).</p> <p>EMG was amplified, bandpass filtered (20–450 Hz), full-wave rectified, and normalized to MVIC. Mean EMG during the <a href="/terms/concentric-contraction/" class="term-link" data-slug="concentric-contraction" title="concentric phase">concentric phase</a> was the primary outcome measure.</p> <p><strong>Statistical Analysis</strong></p> <p>A 2 (height: high vs. low) x 2 (width: wide vs. narrow) repeated-measures ANOVA was used to evaluate main effects and interactions for each muscle. Post hoc t-tests with Bonferroni correction followed significant main effects. Significance was set at p 0.05.</p>

Results and Discussion

<h2>Results and Discussion</h2> <p><strong>Effect of Foot Height on <a href="/terms/muscle-activation/" class="term-link" data-slug="muscle-activation" title="Muscle Activation">Muscle Activation</a></strong></p> <p>Foot height produced a significant main effect on biceps femoris (F(1,23) = 18.4; p 0.001; η²p = 0.44) and gluteus maximus activation (F(1,23) = 14.7; p = 0.001; η²p = 0.39). High foot placement elicited significantly greater biceps femoris (p 0.001) and gluteus maximus (p = 0.001) activation compared to low placement. Conversely, low foot placement produced significantly greater vastus lateralis (p = 0.008) and rectus femoris activation (p = 0.003).</p> <table> <thead> <tr> <th>Condition</th> <th>Vastus Lateralis (%MVIC)</th> <th>Rectus Femoris (%MVIC)</th> <th>Biceps Femoris (%MVIC)</th> <th>Glut. Max (%MVIC)</th> </tr> </thead> <tbody> <tr> <td>High Narrow</td> <td>58.3 ± 9.7</td> <td>42.1 ± 7.6</td> <td>38.7 ± 8.2</td> <td>51.4 ± 10.1</td> </tr> <tr> <td>High Wide</td> <td>55.7 ± 9.2</td> <td>40.3 ± 7.2</td> <td>41.2 ± 8.7</td> <td>63.8 ± 11.4</td> </tr> <tr> <td>Low Narrow</td> <td>74.6 ± 12.1</td> <td>58.4 ± 9.8</td> <td>24.3 ± 5.8</td> <td>34.2 ± 7.6</td> </tr> <tr> <td>Low Wide</td> <td>70.2 ± 11.8</td> <td>55.1 ± 9.3</td> <td>27.8 ± 6.4</td> <td>45.1 ± 9.2</td> </tr> </tbody> </table> <p><strong>Mechanistic Explanation for Height Effects</strong></p> <p>The height-dependent differences in muscle activation are mechanically intuitive. High foot placement increases the effective hip flexion angle at the bottom of the movement. A greater hip flexion angle positions the gluteus maximus at a mechanically advantageous position (longer moment arm) for contributing to hip extension during the <a href="/terms/concentric-contraction/" class="term-link" data-slug="concentric-contraction" title="concentric phase">concentric phase</a>. The hamstrings, as biarticular muscles crossing both the hip and knee, are more favorably positioned to assist hip extension when the hip is more flexed and the knee is less flexed (as occurs in the high foot position at the bottom of the movement) [5].</p> <p>Low foot placement limits hip flexion and places the bottom-position joint angles in a more knee-flexion-dominant configuration. This position increases the moment arm of the quadriceps as knee extensors and reduces the mechanical advantage of the posterior chain muscles, resulting in the observed shift toward quadriceps-dominant activation.</p> <p><strong>Effect of Stance Width</strong></p> <p>Stance width significantly affected gluteus maximus activation (p = 0.004; η²p = 0.32) with a significant height-by-width interaction (p = 0.011). The high-wide condition produced the greatest gluteus maximus activation (63.8 ± 11.4% MVIC) of all four conditions, representing 24% greater activation than the high-narrow condition. This interaction indicates that wide stance is most beneficial for gluteal activation when combined with high foot placement — the two manipulations are synergistic.</p> <p>Stance width also significantly increased adductor longus activation (p = 0.002), consistent with the increased hip abduction angle in the wide stance requiring greater adductor and gluteus maximus co-contraction to maintain pelvic stability.</p> <p>Vastus medialis oblique activation was not significantly affected by either foot height (p = 0.26) or stance width (p = 0.31), contrary to the common belief that low or wide placement selectively recruits the VMO. The data do not support this belief.</p> <p><strong>Clinical and Practical Significance</strong></p> <p>These data provide a mechanistic basis for foot placement strategies that are commonly used by coaches and trainers but have lacked clear empirical support. The consistent finding that foot height independently and substantially affects the quadriceps-to-posterior-chain activation ratio offers practitioners a simple and effective means of targeting different muscle groups with the same exercise.</p>

Practical Applications

<h2>Practical Applications</h2> <p><strong>Strategic Foot Placement Based on Training Goals</strong></p> <p>The evidence from this study allows specific, goal-directed recommendations for leg press foot placement:</p> <p><strong>For Quadriceps Emphasis:</strong> - Use low foot placement (lower third of footplate) - Maintain hip-width or slightly narrower stance - This configuration maximizes quadriceps activation, particularly vastus lateralis and rectus femoris - Ideal for individuals targeting quadriceps <a href="/terms/muscle-hypertrophy/" class="term-link" data-slug="muscle-hypertrophy" title="hypertrophy">hypertrophy</a> or strength as a primary goal, or those with adequate posterior chain development from deadlifts and hip thrust work</p> <p><strong>For Gluteus Maximus and Hamstring Emphasis:</strong> - Use high foot placement (upper third of footplate) - Combine with wide stance for maximum gluteal activation - High-wide placement produces the highest gluteus maximus and biceps femoris activation - Valuable for individuals who cannot perform heavy hip thrusts or Romanian deadlifts due to equipment constraints, injury, or preference</p> <p><strong>For Balanced Lower-Body Development:</strong> - Rotate foot placement configurations across training sessions - Day 1: Low narrow (quadriceps focus) - Day 2 or following week: High wide (posterior chain focus) - This systematic variation ensures comprehensive lower-body stimulus</p> <p><strong>Practical Implementation in Programming</strong></p> <p>The leg press can serve multiple roles depending on foot placement:</p> <table> <thead> <tr> <th>Role</th> <th>Foot Placement</th> <th>Sets/Reps</th> <th>Notes</th> </tr> </thead> <tbody> <tr> <td>Quad-dominant compound</td> <td>Low, narrow</td> <td>4 x 6–10</td> <td>Heavy loading, primary movement</td> </tr> <tr> <td>Glute/ham accessory</td> <td>High, wide</td> <td>3 x 12–15</td> <td>Moderate load, pause at bottom</td> </tr> <tr> <td>Finishing/metabolic</td> <td>Low, narrow</td> <td>2–3 x 20–30</td> <td>Light load, high reps</td> </tr> </tbody> </table> <p><strong>Technique Details for Each Placement</strong></p> <p>High foot placement: The heel should be placed approximately at the level of the upper footplate edge. Ensure the heel is flat on the plate (not elevated) to maintain posterior chain engagement. At the bottom position, the knees should track over the second toe and not collapse inward. The greater depth of hip flexion in this position means the lower back may tend to lift off the seat; maintain contact with the seat by engaging the core and avoiding excessive depth that compromises lumbar position.</p> <p>Low foot placement: Feet are positioned near the lower edge of the footplate, with emphasis on the ball of the foot and mid-foot contact. The reduced hip flexion means the knee travels more directly forward, increasing patellar <a href="/terms/tendon/" class="term-link" data-slug="tendon" title="tendon">tendon</a> loading. Individuals with patellar tendon sensitivity should monitor for discomfort at low foot placements with heavy loads.</p> <p><strong>Common Errors and Corrections</strong></p> <ul> <li>Allowing knees to cave inward: Push knees out in line with toes throughout the movement</li> <li>Lifting heels off the footplate: Keep the entire foot flat; heel elevation shifts load to the quadriceps-only and may cause knee discomfort</li> <li>Excessive <a href="/terms/range-of-motion/" class="term-link" data-slug="range-of-motion" title="range of motion">range of motion</a> at high placement: Stop when the glutes begin to lift from the seat (approximately 90 degrees of hip flexion); going deeper does not increase <a href="/terms/muscle-activation/" class="term-link" data-slug="muscle-activation" title="muscle activation">muscle activation</a> and may strain the lumbar spine</li> <li>Locking out aggressively at the top: Maintain slight knee flexion at the top to keep tension on the muscles and reduce joint stress</li> </ul>