Hypertrophy
Narrative Review
2018
Effects of drop set resistance training on acute stress indicators and long-term muscle hypertrophy and strength
By Jozo Grgic and Brad J. Schoenfeld
Journal of Sports Sciences, 36(16), pp. 1823-1831
<h2>Abstract</h2>
<p><a href="/terms/drop-set/" class="term-link" data-slug="drop-set" title="Drop sets">Drop sets</a> — a technique in which resistance is immediately reduced following initial set failure and training continues without rest — have gained widespread popularity in resistance training practice as a time-efficient method for accumulating <a href="/terms/training-volume/" class="term-link" data-slug="training-volume" title="training volume">training volume</a>. Grgic and Schoenfeld (2018) conducted a narrative review examining the acute physiological responses and long-term adaptations associated with drop set training. Evidence suggests that drop sets produce comparable hypertrophic outcomes to traditional training protocols while significantly reducing session duration. The primary proposed mechanism is enhanced <a href="/terms/metabolic-stress/" class="term-link" data-slug="metabolic-stress" title="metabolic stress">metabolic stress</a>, characterized by greater lactate accumulation, cell swelling, and anabolic hormone release relative to volume-equated traditional sets. In studies where total training volume was not equated, drop sets frequently generated greater <a href="/terms/volume-load/" class="term-link" data-slug="volume-load" title="total volume load">total volume load</a> within a shorter time frame. Practical implications favor the incorporation of drop sets as a time-efficient strategy, particularly for isolation exercises where technical failure risk is lower. Optimal implementation appears to involve 1-2 drops per set with load reductions of 20-25%, applied selectively to final sets of a training session rather than as a replacement for all traditional sets.</p>
<h2>Introduction</h2>
<p>Time is a recurring constraint in exercise adherence. Many individuals who recognize the benefits of resistance training nonetheless report insufficient time as a primary barrier to consistent practice [1]. <a href="/terms/drop-set/" class="term-link" data-slug="drop-set" title="Drop sets">Drop sets</a> — also called descending sets or strip sets — offer a potential solution by enabling trainees to accumulate meaningful <a href="/terms/training-volume/" class="term-link" data-slug="training-volume" title="training volume">training volume</a> in substantially less time than traditional straight-set approaches.</p>
<p>The drop set technique involves performing an initial set to <a href="/terms/momentary-muscular-failure/" class="term-link" data-slug="momentary-muscular-failure" title="momentary muscular failure">momentary muscular failure</a>, immediately reducing the load by a predetermined amount (typically 20-30%), and continuing to perform repetitions until failure again occurs. This process may be repeated one or more times within a single set cluster. The result is an extended set that produces an exceptionally high degree of <a href="/terms/metabolic-stress/" class="term-link" data-slug="metabolic-stress" title="metabolic fatigue">metabolic fatigue</a> and mechanical work without the <a href="/terms/inter-set-rest-interval/" class="term-link" data-slug="inter-set-rest-interval" title="inter-set rest">inter-set rest</a> periods that characterize traditional training. Arnold Schwarzenegger popularized this technique as a cornerstone of high-intensity bodybuilding methodology during the 1970s, yet its scientific examination remained limited until comparatively recently [2].</p>
<p>From a mechanistic standpoint, drop sets are hypothesized to elicit <a href="/terms/muscle-hypertrophy/" class="term-link" data-slug="muscle-hypertrophy" title="hypertrophy">hypertrophy</a> through two primary pathways that differ in emphasis from traditional training. First, the removal of rest periods preserves and amplifies metabolic stress — the accumulation of metabolites including lactate, hydrogen ions, and inorganic phosphate that is thought to stimulate anabolic signaling through cell swelling, reactive oxygen species production, and growth hormone secretion [3]. Second, by continuing to recruit progressively lower-threshold motor units as higher-threshold units fatigue, drop sets may expose a broader cross-section of muscle fibers to sufficient mechanical stimulus within a single set cluster.</p>
<p>Grgic and Schoenfeld (2018) undertook this review to synthesize available evidence on drop sets, evaluate the quality of that evidence, and derive actionable recommendations for practitioners. This required distinguishing between studies that equated total training volume between drop set and traditional conditions — where metabolic stress differences would be the primary differentiating factor — and those that did not equate volume, where drop sets would also produce greater absolute training stimulus [4].</p>
<h2>Evidence Review</h2>
<h3>Acute Physiological Responses</h3>
<p>Short-term studies examining the immediate physiological consequences of <a href="/terms/drop-set/" class="term-link" data-slug="drop-set" title="drop sets">drop sets</a> reveal a distinctive metabolic signature. Compared to traditional sets performed with equivalent total volume, drop set protocols produce significantly higher blood lactate concentrations — often exceeding 10-12 mmol/L during high-intensity drop set clusters [5]. This is accompanied by greater elevations in growth hormone (GH), a hormone with known anabolic and lipolytic properties, though the physiological significance of these transient GH spikes for actual <a href="/terms/muscle-hypertrophy/" class="term-link" data-slug="muscle-hypertrophy" title="muscle hypertrophy">muscle hypertrophy</a> remains debated [6].</p>
<p>Cell swelling, another proposed hypertrophic mechanism, appears to be more pronounced following drop sets. The sustained occlusion-like metabolic environment created by eliminating rest periods restricts venous return and promotes intracellular fluid accumulation, stretching the cellular membrane and potentially signaling anabolic pathways including <a href="/terms/mtor/" class="term-link" data-slug="mtor" title="mTORC1">mTORC1</a> and the PI3K-Akt cascade [7].</p>
<h3>Long-Term Hypertrophy Outcomes</h3>
<p>The available longitudinal evidence, while limited in scope, generally supports the position that drop sets produce hypertrophic outcomes comparable to traditional sets. Fink et al. compared drop set training against traditional sets in untrained subjects over 6 weeks and found no statistically significant difference in muscle <a href="/terms/cross-sectional-area/" class="term-link" data-slug="cross-sectional-area" title="cross-sectional area">cross-sectional area</a> gains, despite drop set sessions requiring approximately 50% less time [8]. A similar pattern was observed by Angleri et al. in a longer (16-week) study examining the quadriceps, where drop set and traditional set conditions produced equivalent hypertrophy when total repetitions were equated.</p>
<p>The key nuance emerging from the literature is the role of volume equating. When studies fail to equate total <a href="/terms/training-volume/" class="term-link" data-slug="training-volume" title="training volume">training volume</a> — allowing drop sets to generate more total repetitions — drop set conditions tend to produce superior hypertrophy, consistent with the <a href="/terms/dose-response-relationship/" class="term-link" data-slug="dose-response-relationship" title="dose-response relationship">dose-response relationship</a> between volume and muscle growth. When volume is equated, outcomes are generally similar.</p>
<h3>Strength Outcomes</h3>
<p>Evidence for strength adaptations following drop set training is less consistent than for hypertrophy. Some studies report comparable strength gains between drop set and traditional protocols on multi-joint movements such as the squat and leg press [9]. However, the reduced <a href="/terms/time-under-tension/" class="term-link" data-slug="time-under-tension" title="time under tension">time under tension</a> at heavier loads during drop sets may limit maximal strength development compared to protocols that maintain high loads throughout all sets — a consideration for athletes prioritizing strength alongside hypertrophy.</p>
<table>
<thead>
<tr>
<th>Outcome</th>
<th>Drop Sets vs. Traditional Sets</th>
</tr>
</thead>
<tbody>
<tr>
<td>Hypertrophy (equated volume)</td>
<td>Comparable</td>
</tr>
<tr>
<td>Hypertrophy (non-equated volume)</td>
<td>Favors drop sets</td>
</tr>
<tr>
<td>Maximal strength</td>
<td>Comparable or slightly favors traditional</td>
</tr>
<tr>
<td>Session duration</td>
<td>Significantly shorter with drop sets</td>
</tr>
<tr>
<td><a href="/terms/metabolic-stress/" class="term-link" data-slug="metabolic-stress" title="Metabolic stress">Metabolic stress</a></td>
<td>Higher with drop sets</td>
</tr>
</tbody>
</table>
<h2>Discussion</h2>
<h3>Reframing the Efficiency Argument</h3>
<p>The central practical contribution of the <a href="/terms/drop-set/" class="term-link" data-slug="drop-set" title="drop set">drop set</a> literature is not that drop sets are superior to traditional training, but that they are approximately equivalent while requiring substantially less time. This efficiency advantage has meaningful implications for adherence. <a href="/terms/intermittent-fasting/" class="term-link" data-slug="intermittent-fasting" title="If">If</a> a trainee can achieve similar <a href="/terms/muscle-hypertrophy/" class="term-link" data-slug="muscle-hypertrophy" title="hypertrophy">hypertrophy</a> in 45 minutes with drop sets as they would in 75 minutes with traditional sets, the former approach substantially reduces a primary barrier to consistent resistance training participation [10].</p>
<p>This framing shifts the question from "Are drop sets better?" to "What is the cost-benefit ratio of drop sets compared to traditional training for a given trainee's goals and constraints?" For individuals with limited time, the answer is clearly favorable. For competitive strength athletes who require maximal force production and technical refinement under heavy loads, traditional set structures may remain preferable.</p>
<h3>The Role of <a href="/terms/metabolic-stress/" class="term-link" data-slug="metabolic-stress" title="Metabolic Stress">Metabolic Stress</a></h3>
<p>The review highlights metabolic stress as the primary mechanistic candidate distinguishing drop sets from traditional training. Under the three-mechanism model of hypertrophy proposed by Schoenfeld [11], <a href="/terms/mechanical-tension/" class="term-link" data-slug="mechanical-tension" title="mechanical tension">mechanical tension</a> is the dominant driver of <a href="/terms/myofibrillar-hypertrophy/" class="term-link" data-slug="myofibrillar-hypertrophy" title="myofibrillar hypertrophy">myofibrillar hypertrophy</a>, while metabolic stress may contribute disproportionately to <a href="/terms/sarcoplasmic-hypertrophy/" class="term-link" data-slug="sarcoplasmic-hypertrophy" title="sarcoplasmic hypertrophy">sarcoplasmic hypertrophy</a> — the expansion of the fluid and glycolytic enzyme content within muscle cells. If this distinction is correct, the hypertrophic profile of drop set training might differ qualitatively from that of traditional heavy-load training even when total hypertrophy is quantitatively similar: drop sets may preferentially expand sarcoplasmic components while traditional loading drives greater myofibrillar protein accretion.</p>
<p>This hypothesis, while theoretically interesting, remains speculative. Current evidence is insufficient to confirm that the two types of hypertrophy are meaningfully distinct in functional or aesthetic terms [12].</p>
<h3><a href="/terms/motor-unit/" class="term-link" data-slug="motor-unit" title="Motor Unit">Motor Unit</a> Recruitment and <a href="/terms/muscle-fiber/" class="term-link" data-slug="muscle-fiber" title="Muscle Fiber">Muscle Fiber</a> Activation</h3>
<p>A practical observation supporting drop sets is their capacity to fatigue high-threshold motor units early in the set, then recruit lower-threshold units as the load decreases. This progressive fatigue-recruitment cascade may expose a greater proportion of the total muscle fiber pool to hypertrophic stimulation within a single set cluster than a traditional single-effort set at constant load, potentially explaining why non-volume-equated drop sets favor hypertrophy.</p>
<h3>Limitations of Available Evidence</h3>
<p>The drop set literature remains characterized by small sample sizes, short intervention durations, and predominant use of untrained subjects — a population that responds to almost any resistance training stimulus. Extrapolating these findings to highly trained individuals warrants caution. Well-controlled, long-duration studies in experienced lifters are needed to determine whether the efficiency advantages of drop sets persist at higher training levels [13].</p>
<h2>Practical Recommendations</h2>
<h3>When to Use <a href="/terms/drop-set/" class="term-link" data-slug="drop-set" title="Drop Sets">Drop Sets</a></h3>
<p>Drop sets are most appropriate in the following circumstances:</p>
<ul>
<li><strong>Time-constrained sessions:</strong> When training time is limited (30-45 minutes), replacing the final 1-2 sets of each exercise with drop sets can preserve training stimulus while reducing session duration by 25-40%.</li>
<li><strong><a href="/terms/muscle-hypertrophy/" class="term-link" data-slug="muscle-hypertrophy" title="Hypertrophy">Hypertrophy</a> phases:</strong> During dedicated muscle-building phases where <a href="/terms/metabolic-stress/" class="term-link" data-slug="metabolic-stress" title="metabolic stress">metabolic stress</a> and volume accumulation are priorities, drop sets serve as an effective high-intensity technique.</li>
<li><strong>Isolation exercises:</strong> Movements such as lateral raises, bicep curls, tricep pushdowns, and leg extensions are ideally suited for drop sets because technical breakdown under fatigue poses minimal injury risk.</li>
</ul>
<h3>Load Reduction Guidelines</h3>
<p>Empirical practice and available research support load reductions of 20-25% per drop. A single drop (one reduction) is the most practical approach for most exercises and training contexts, while 2-3 drops can be used on isolation exercises when a very high metabolic stimulus is desired. Reductions larger than 25-30% may shift the exercise so far into the endurance repetition range that hypertrophic stimulus diminishes.</p>
<p><strong>Example: Dumbbell Lateral Raise Drop Set</strong>
- Initial set: 12 kg × failure (12-15 reps)
- Drop 1: 10 kg × failure (10-12 reps)
- Drop 2: 8 kg × failure (10-12 reps)</p>
<h3>Positioning in the Workout</h3>
<p>Drop sets are most effectively placed at the end of a training session or as the final set of a given exercise. Using drop sets early in a workout risks premature fatigue that compromises form and performance on subsequent exercises. Treating drop sets as a finisher technique preserves quality on the primary training stimuli while adding an efficient high-metabolic-stress component at the end.</p>
<h3>Frequency of Application</h3>
<p>Drop sets generate significant metabolic fatigue and should not be applied to every exercise in every session. A practical guideline is 1-2 drop set applications per session, focusing on muscle groups or exercises identified as lagging. Excessive use of drop sets can accumulate fatigue that impairs recovery between sessions, potentially negating the volume advantages they provide.</p>
<h3><a href="/terms/compound-exercise/" class="term-link" data-slug="compound-exercise" title="Compound Exercise">Compound Exercise</a> Caution</h3>
<p>While drop sets can theoretically be applied to compound movements such as squats or deadlifts, doing so requires extreme caution. Technical breakdown under combined metabolic fatigue and load is a significant injury risk. <a href="/terms/intermittent-fasting/" class="term-link" data-slug="intermittent-fasting" title="If">If</a> applied to compound movements, experienced lifters should use a spotter, restrict drops to machine-based compound exercises (leg press, seated row, cable pulldowns), and keep drops conservative (one drop maximum).</p>