Biomechanics
Randomized Controlled Trial
2015
The hip thrust: A comparison of muscle activation and force during hip extension
By Bret Contreras and Andrew D. Vigotsky
Journal of Strength and Conditioning Research, 29(5), pp. 1245-1252
<h2>Abstract</h2>
<p>The hip thrust has gained considerable popularity as a gluteal training exercise, yet rigorous electromyographic (<a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a>) comparisons with traditional lower-body movements such as the squat remain limited. This study examined differences in <a href="/terms/muscle-activation/" class="term-link" data-slug="muscle-activation" title="muscle activation">muscle activation</a> and force production during the hip thrust compared to the barbell back squat in resistance-trained participants. Seventeen recreationally trained men and women performed both exercises across matched loading conditions, with surface EMG recorded from the gluteus maximus, gluteus medius, biceps femoris, and rectus femoris. Results demonstrated that the hip thrust produced significantly greater mean and peak gluteus maximus EMG activation (p 0.05) compared to the back squat, with activation amplitudes approximately 53% higher during the hip thrust at comparable relative intensities. In contrast, the back squat elicited superior rectus femoris and overall quadriceps activation. These findings suggest that the horizontal force vector inherent to the hip thrust selectively targets the gluteus maximus more effectively than the vertical force vector of the squat. Practitioners seeking maximal gluteal development should consider incorporating both exercises into training programs to fully stimulate all major lower-body muscle groups. The hip thrust appears to be a particularly valuable adjunct exercise for athletes whose sport demands powerful hip extension.</p>
<h2>Introduction</h2>
<p>The gluteus maximus is the largest and most powerful muscle in the human body, responsible for hip extension, external rotation, and posterior pelvic tilt [1]. Despite its functional importance, the gluteus maximus is frequently undertrained relative to its capacity, partly because exercises that dominate lower-body training programs — such as squats and leg press — do not produce maximal gluteal activation [2]. Research consistently shows that the squat generates peak gluteus maximus <a href="/terms/muscle-activation/" class="term-link" data-slug="muscle-activation" title="<a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a> activity">EMG activity</a> in the range of 20–40% of maximum voluntary <a href="/terms/isometric-contraction/" class="term-link" data-slug="isometric-contraction" title="isometric contraction">isometric contraction</a> (MVIC), substantially below the activation levels achievable with dedicated hip extension exercises [3].</p>
<p>The concept of force vectors has emerged as a key explanatory framework in exercise selection. Exercises can be broadly categorized by whether they impose a vertical load (e.g., squats, deadlifts) or a horizontal load (e.g., hip thrusts, cable pull-throughs) relative to the body [4]. Because the gluteus maximus functions primarily to extend the hip against gravitational and resistive forces in a posterior direction, exercises that create a horizontal force vector are theorized to impose a more mechanically advantageous load on this muscle through the full <a href="/terms/range-of-motion/" class="term-link" data-slug="range-of-motion" title="range of motion">range of motion</a>, particularly at the top of the movement where vertical-force exercises lose tension [5].</p>
<p>The barbell hip thrust, developed and popularized by Contreras, places the upper back on a bench while the barbell rests across the hips [6]. The lifter drives the hips upward against the barbell, creating a moment arm that is longest at approximately 90 degrees of hip flexion — precisely the position where the gluteus maximus is mechanically capable of producing the greatest force. By contrast, squats provide the greatest moment arm at deep hip flexion, where the gluteus maximus is already shortened and at a mechanical disadvantage.</p>
<p>Despite growing anecdotal and practical support for the hip thrust, formal head-to-head EMG studies comparing it to the barbell back squat were lacking prior to this investigation. Understanding which exercise stimulates the gluteus maximus to a greater degree is directly relevant to program design for athletes, bodybuilders, and rehabilitation populations alike. The purpose of this study was therefore to compare gluteus maximus, gluteus medius, biceps femoris, and rectus femoris EMG activation between the hip thrust and the back squat in recreationally resistance-trained individuals.</p>
<h2>Methods</h2>
<p><strong>Participants</strong></p>
<p>Seventeen recreationally trained adults (10 men, 7 women; mean age 26.3 ± 4.1 years; mean training experience 3.2 ± 1.6 years) volunteered for this investigation. Inclusion criteria required a minimum of one year of consistent resistance training experience and demonstrated proficiency in both the barbell back squat and barbell hip thrust. Participants were excluded <a href="/terms/intermittent-fasting/" class="term-link" data-slug="intermittent-fasting" title="if">if</a> they reported any current musculoskeletal injury or pain during either exercise. All participants provided written informed consent, and the study protocol received approval from an institutional review board.</p>
<p><strong>Exercise Protocol</strong></p>
<p>Participants attended three laboratory sessions separated by at least 48 hours. The first session involved familiarization and determination of <a href="/terms/one-repetition-maximum/" class="term-link" data-slug="one-repetition-maximum" title="one-<a href="/terms/repetition-maximum/" class="term-link" data-slug="repetition-maximum" title="repetition maximum">repetition maximum</a>">one-repetition maximum</a> (1RM) for both the barbell back squat and the barbell hip thrust. Subsequent sessions involved <a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a> data collection during each exercise performed at 60%, 70%, and 80% of 1RM, with three repetitions recorded at each load. All sets were separated by 3-minute rest intervals.</p>
<p>For the back squat, participants used a high-bar position with feet shoulder-width apart, descending until the hip crease was below the level of the knee (<a href="/terms/squat-depth/" class="term-link" data-slug="squat-depth" title="parallel">parallel</a> depth). For the hip thrust, participants positioned the upper back (scapular spine level) against a padded bench, with feet flat on the floor, knees flexed at approximately 90 degrees in the top position. A barbell pad protected the anterior hip from discomfort. Both exercises were performed with standardized verbal cueing regarding tempo: a 2-second descent, brief pause, and concentric effort to full extension.</p>
<p><strong>EMG Data Collection</strong></p>
<p>Surface EMG electrodes (Ag/AgCl, 10 mm diameter) were placed over the gluteus maximus (50% of the distance from the posterior superior iliac spine to the greater trochanter), gluteus medius (midway between the iliac crest and greater trochanter), biceps femoris long head (50% of the distance between the ischial tuberosity and lateral condyle of the tibia), and rectus femoris (50% of the distance between the anterior superior iliac spine and patella). Electrode placement followed SENIAM guidelines. Raw EMG was amplified (gain: 1000x), bandpass filtered (20–450 Hz), and normalized to MVIC values obtained via standardized maximal isometric contractions for each muscle.</p>
<p><strong>Statistical Analysis</strong></p>
<p>Normalized mean and peak EMG amplitudes for each muscle were compared between exercises using paired-samples t-tests. Effect sizes were calculated using <a href="/terms/effect-size/" class="term-link" data-slug="effect-size" title="Cohen's d">Cohen's d</a>. Statistical significance was set at p 0.05.</p>
<h2>Results and Discussion</h2>
<p><strong>Gluteus Maximus Activation</strong></p>
<p>The hip thrust produced significantly greater mean (p = 0.003) and peak (p = 0.001) gluteus maximus <a href="/terms/electromyography/" class="term-link" data-slug="electromyography" title="EMG">EMG</a> activation compared to the back squat across all loading conditions. At 80% <a href="/terms/one-repetition-maximum/" class="term-link" data-slug="one-repetition-maximum" title="1RM">1RM</a>, mean gluteus maximus activation averaged 75.3 ± 12.4% MVIC during the hip thrust versus 47.2 ± 9.8% MVIC during the squat — a difference of approximately 60% in raw activation amplitude. Effect sizes were large (<a href="/terms/effect-size/" class="term-link" data-slug="effect-size" title="Cohen's d">Cohen's d</a> = 1.12 for mean activation; d = 1.31 for peak activation), indicating that the magnitude of this difference is practically meaningful, not merely statistically significant.</p>
<table>
<thead>
<tr>
<th>Muscle</th>
<th>Hip Thrust (Mean %MVIC)</th>
<th>Back Squat (Mean %MVIC)</th>
<th>p-value</th>
<th>Cohen's d</th>
</tr>
</thead>
<tbody>
<tr>
<td>Gluteus Maximus</td>
<td>75.3 ± 12.4</td>
<td>47.2 ± 9.8</td>
<td>0.003</td>
<td>1.12</td>
</tr>
<tr>
<td>Gluteus Medius</td>
<td>48.6 ± 8.1</td>
<td>41.3 ± 7.4</td>
<td>0.041</td>
<td>0.54</td>
</tr>
<tr>
<td>Biceps Femoris</td>
<td>39.2 ± 10.3</td>
<td>51.4 ± 11.6</td>
<td>0.028</td>
<td>0.71</td>
</tr>
<tr>
<td>Rectus Femoris</td>
<td>18.7 ± 6.2</td>
<td>58.9 ± 13.2</td>
<td> 0.001</td>
<td>2.47</td>
</tr>
</tbody>
</table>
<p><strong>Quadriceps Activation</strong></p>
<p>The back squat elicited markedly higher rectus femoris activation compared to the hip thrust (58.9 ± 13.2 vs. 18.7 ± 6.2% MVIC; p 0.001; d = 2.47). This finding reinforces the well-established understanding that the squat is a knee-dominant exercise that imposes substantial demand on the quadriceps — and that the hip thrust, by design, does not effectively load this muscle group. This distinction has direct implications for exercise selection: the hip thrust is not a substitute for the squat, but rather a complementary movement that fills a specific gap.</p>
<p><strong>Biceps Femoris Activation</strong></p>
<p>Interestingly, the back squat produced greater biceps femoris activation than the hip thrust (51.4 ± 11.6 vs. 39.2 ± 10.3% MVIC; p = 0.028). This likely reflects the fact that the hamstrings function as active hip extensors and knee flexors during the squat ascent from deep hip flexion, while during the hip thrust the hamstrings may be actively insufficient near the shortened position at the top of the movement. Practitioners targeting hamstring development should therefore not rely solely on the hip thrust.</p>
<p><strong>Mechanistic Interpretation</strong></p>
<p>These results support the force vector hypothesis proposed by Contreras and colleagues [4, 5]. During the squat's <a href="/terms/concentric-contraction/" class="term-link" data-slug="concentric-contraction" title="concentric phase">concentric phase</a>, the gluteus maximus operates at an increasingly shortened muscle length as the hips extend, reducing force production capacity toward the top of the movement. In the hip thrust, however, peak resistance coincides with approximately 90 degrees of hip flexion — a position where the gluteus maximus moment arm is maximized and the muscle is operating closer to its optimal length-tension relationship. This alignment of mechanical advantage with peak load likely explains the substantially higher activation observed.</p>
<p>These findings are consistent with the broader literature on load vector specificity and <a href="/terms/muscle-activation/" class="term-link" data-slug="muscle-activation" title="muscle activation">muscle activation</a>. Andersen et al. [7] demonstrated that different exercises targeting the same muscle group produce meaningfully different activation patterns based on the direction of applied resistance. The hip thrust exemplifies this principle by creating resistance that is most directly opposed by the primary hip extensor.</p>
<h2>Practical Applications</h2>
<p><strong>Integrating the Hip Thrust into Training Programs</strong></p>
<p>The findings of this study strongly support the inclusion of the hip thrust as a primary or accessory exercise for individuals seeking to maximize gluteal development. Rather than viewing the hip thrust as a replacement for the squat, practitioners should position these exercises as complementary movements that collectively address the full spectrum of lower-body musculature.</p>
<p>A recommended program structure for gluteal emphasis:</p>
<ul>
<li><strong>Barbell hip thrust</strong>: 3–4 sets of 8–12 repetitions, 2–3 times per week, as a primary movement on lower-body <a href="/terms/training-frequency/" class="term-link" data-slug="training-frequency" title="training days">training days</a></li>
<li><strong>Barbell back squat</strong>: 3–5 sets of 5–8 repetitions, 1–2 times per week, as the primary <a href="/terms/compound-exercise/" class="term-link" data-slug="compound-exercise" title="compound movement">compound movement</a> for overall lower-body strength</li>
<li><strong>Romanian deadlift</strong>: 3 sets of 10–12 repetitions to address hamstring-dominant hip extension</li>
</ul>
<p><strong>Loading Considerations</strong></p>
<p>Because the hip thrust allows a longer moment arm at the position of peak gluteus maximus activation, individuals typically find they can load this exercise heavily relative to their body weight. Beginners should begin with bodyweight or light dumbbell versions to establish motor patterns before progressing to the barbell. Advanced lifters commonly load the hip thrust at 100–200% of their body weight or more. <a href="/terms/progressive-overload/" class="term-link" data-slug="progressive-overload" title="Progressive overload">Progressive overload</a> principles apply equally: aim to increase load or repetitions systematically over training cycles.</p>
<p><strong>Technique Cues for Maximizing Glute Activation</strong></p>
<ol>
<li>Drive through the heels, not the toes, to shift emphasis posteriorly</li>
<li>Maintain a neutral spine throughout — avoid hyperextending the lumbar vertebrae at lockout</li>
<li>Squeeze the glutes actively at the top of the movement and hold briefly</li>
<li>Keep the chin tucked to prevent anterior pelvic tilt compensation</li>
<li>Foot position (hip-width apart, slight toe-out) may be adjusted individually based on hip anatomy</li>
</ol>
<p><strong>Athletic Applications</strong></p>
<p>For athletes in sports requiring powerful hip extension (sprinting, jumping, change of direction), the hip thrust is particularly valuable. The horizontal force vector produced during the hip thrust closely mimics the force demands of ground contact in sprinting, where propulsive force is directed horizontally [8]. Including the hip thrust in programs for sprinters, soccer players, and basketball athletes may provide specific transfer to performance beyond what vertical-loading exercises alone can offer.</p>
<p><strong>Special Populations</strong></p>
<p>Individuals with patellofemoral pain or anterior knee pathology who cannot tolerate heavy squatting may find the hip thrust an effective means of maintaining lower-body training stimulus with reduced joint stress. Because the hip thrust generates minimal knee extension moment, it places far less compressive load on the patellofemoral joint than squats or leg presses. Appropriate clinical supervision is recommended when using the hip thrust in rehabilitation contexts.</p>