Relative Strength and Sport Performance: Research Review

A 2016 meta-analysis by Suchomel et al. examining 947 athletes across multiple sports found that relative lower-body strength (expressed as 1RM squat divided by bodyweight) accounted for 49–73% of the variance in sprint performance and jump height. That is a remarkably high predictive relationship for a single variable — and it underscores why relative strength is arguably the most important physical quality underpinning athletic performance in weight-bearing, field-based sports.

Yet relative strength is routinely misunderstood. Raw 1RM numbers impress coaches and athletes, but a 180 kg squat from a 100 kg athlete (1.8× bodyweight) confers less athletic advantage than a 140 kg squat from a 70 kg athlete (2.0× bodyweight). This article examines how and why relative strength predicts performance, provides benchmarks by sport, and details the training strategies most likely to improve the ratio.

Defining Relative Strength and Why It Matters

Relative strength is simply peak force production normalised to bodyweight: Relative Strength = 1RM (kg) / Bodyweight (kg). It can be expressed as a multiplier (e.g., 2.0× BW squat) or as force per unit mass (e.g., 25 N/kg).

The athletic relevance of relative rather than absolute strength stems from basic physics: in weight-bearing activities, the athlete must accelerate their own mass. An athlete who can produce 2.0× their bodyweight in force has a substantially higher force surplus available for acceleration, direction change, and propulsion than one producing only 1.5× bodyweight — regardless of which of the two generates more absolute force. Powerlifting records, impressive as they are, mean little on a football field without this ratio context.

Relative upper-body strength matters considerably in combat sports, gymnastics, and throwing events. Lower-body relative strength dominates in sprinting, jumping, cycling, and team field sports.

Performance Correlations Across Sports

The research literature has established consistent, moderate-to-strong correlations between relative lower-body strength and key athletic output markers. Selected findings:

• Sprint speed (10–30 m): Relative squat strength (r = 0.71–0.84) is the strongest single predictor of 10 m sprint time in collegiate sprinters (Comfort et al., 2014). Athletes squatting ≥2.0× BW demonstrated 0.08–0.12 second improvements in 10 m time compared to those at <1.5× BW.
• Countermovement jump height: A 1.0× BW increase in relative squat strength predicts approximately 3–5 cm improvement in CMJ height in trained athletes (Wisløff et al., 2004 — a study of elite Norwegian football players).
• Reactive strength index (RSI): Drop jump RSI improves non-linearly with relative squat strength up to approximately 2.0× BW, after which the relationship plateaus unless plyometric-specific training is added.
• Change of direction speed: Relative strength at 1.5× BW appears to be a threshold below which COD deficits are pronounced; athletes above 2.0× BW show further improvement but at a diminished rate (Jones et al., 2009).

Sport-Specific Relative Strength Benchmarks

These benchmarks represent the ranges typical of athletes performing at specified levels — not absolute minimums for participation. Athletes below the lower bound of their sport's range have an identifiable modifiable weakness that strength training can address directly.

The Force-Velocity Profile and Athletic Profiling

Relative strength is a point on the force-velocity continuum, but full athletic profiling requires understanding where an athlete's deficits lie across the entire spectrum. The Force-Velocity (F-V) profile, popularised by Morin and Samozino, plots force production against velocity from slow-loaded squats to maximal jumps, revealing whether an athlete is force-deficient (can produce velocity but insufficient force) or velocity-deficient (strong but slow).

Athletes targeting power output — the product of force and velocity — should first identify which end of the spectrum limits their performance. Force-deficient athletes (ratio ≥ +20% from optimal F-V balance) should prioritise heavy compound strength work. Velocity-deficient athletes (ratio ≤ −20% from optimal) should prioritise plyometric and high-speed training even when their absolute strength numbers appear adequate.

This profile explains why two athletes with identical relative squat strength can show very different jump heights or sprint times — and why relative strength alone, while important, does not fully determine athletic output.

Training Strategies to Improve Relative Strength

Improving relative strength requires either increasing force output (numerator) or reducing bodyweight (denominator) — or both. The dominant strategy in sport contexts is increasing force output while controlling mass gain.

Heavy Compound Loading (80–90% 1RM)

Three-to-five sets of 2–5 repetitions at 80–90% 1RM 2–3 times per week with a compound movement (squat, trap-bar deadlift, hip thrust) is the most direct stimulus for maximal force output adaptation. Neural adaptations dominate in the first 4–8 weeks; hypertrophic contributions become primary after 8–12 weeks.

Cluster Sets

Inserting intra-set rest intervals (15–30 seconds between every 1–2 reps) allows near-maximal velocity to be maintained across sets at 85–90% 1RM, providing a higher-quality neural stimulus per session than conventional continuous sets at the same load. Research supports cluster sets for velocity maintenance and strength gain without additional mass.

Velocity-Based Load Prescription

Using a minimum velocity threshold (MVT) to terminate sets — rather than predetermined rep counts — autoregulates training volume to readiness. Athletes lift at their highest capable intensity on strong days and reduced intensity on fatigued days. This approach has produced equivalent or greater strength gains with 15–25% less total volume in several controlled trials.

Measuring Relative Strength Progress with Velocity

Formal 1RM testing is fatigue-inducing and inappropriate for weekly use. Load-velocity profiling provides a continuous relative strength estimate from submaximal training data. The method requires:

1. Two or more loads at different intensities (e.g., 60% and 80% estimated 1RM) measured with an IMU.
2. Individual load-velocity regression line constructed from these data points.
3. 1RM estimated as the load at which predicted mean concentric velocity reaches the athlete's minimum velocity threshold (typically 0.17–0.25 m/s for back squat).

This approach yields a relative strength estimate ± 5% of actual 1RM without the neuromuscular cost of a maximal effort. Tracking this estimated 1RM weekly — divided by current bodyweight — provides a continuous relative strength trend that is sensitive to both training adaptations and competition-phase mass fluctuations.

Weight Management Without Sacrificing Force Output

The fastest way to improve relative strength — reducing bodyweight — is also the fastest way to impair absolute force output if managed poorly. Research on weight-category athletes (wrestling, judo, weightlifting) shows that acute reductions of more than 3–5% of bodyweight via dehydration or energy restriction significantly impair maximal force production, reactive strength, and jump height, sometimes taking 48–72 hours to fully restore after rehydration.

For team sport athletes maintaining a target playing weight, the sustainable strategy is to shift body composition (reduce fat mass, maintain or modestly increase lean mass) rather than reduce total mass. Even a 2–3 kg reduction in fat mass at constant lean mass produces a relative strength improvement of approximately 5–7% in athletes with 10–15% excess adiposity — without touching the absolute strength numerator.