Sex Differences in the Load-Velocity Profile: Evidence Review for VBT Practice

When Torrejón et al. (2019) analyzed load-velocity data from 130 resistance-trained athletes across two exercises, they found that the group-level relationship between relative load (%1RM) and mean concentric velocity was highly reproducible — but also that individual variability around those group curves was large enough to make standardized velocity zones unreliable for roughly one athlete in five. That finding prompted a more pointed question for practitioners working with female athletes: are the mean velocity-zone tables derived predominantly from male cohorts even applicable to women, or do systematic sex differences in the load-velocity profile require separate reference values — or better yet, individualized profiling for every athlete regardless of sex? This evidence review examines what the current literature can and cannot tell us about sex differences in load-velocity relationships, minimal velocity thresholds, fatigue-velocity responses, and inter-set recovery, with direct implications for how velocity zones and auto-regulation thresholds should be set for female athletes in practice.

The load-velocity (LV) profile describes the approximately linear inverse relationship between relative load (%1RM) and the mean concentric velocity (MCV) produced during a resistance exercise performed with maximal intent. Lighter loads are moved faster; heavier loads are moved slower. When this relationship is plotted and a best-fit regression line is constructed, the line can be extrapolated to estimate 1RM — the load at which MCV theoretically reaches the minimal velocity threshold (MVT), a value that represents the slowest velocity at which a lift can be completed.

The LV profile has two practical applications. First, it provides individualized velocity zones — the specific MCV ranges corresponding to each %1RM band (e.g., 60%, 70%, 80%) for a given athlete on a given exercise. Second, it enables ongoing 1RM estimation without maximal testing: measuring MCV at two or three submaximal loads allows the regression line to be reconstructed and extrapolated to the athlete's current MVT, yielding a daily strength estimate. Both applications rest on the assumption that the LV profile is reasonably stable within an individual and reasonably consistent across individuals of similar training status. The sex-difference question directly challenges that second assumption.

The most practically relevant question for coaches is whether female athletes move a given %1RM at systematically different velocities than males. If a male athlete lifts 80% 1RM in the back squat at approximately 0.55 m/s (a common reference value), does a female athlete move 80% 1RM at the same velocity?

The available evidence suggests that group-level LV profiles in the back squat and bench press are broadly similar between sexes, but with meaningful individual and exercise-specific variation. García-Ramos et al. (2019) examined the LV profile in the bench press across male and female trained athletes and reported that the slope and intercept of the LV regression line did not differ significantly between sexes when relative loads were expressed as %1RM. At 80% 1RM, mean concentric velocity averaged 0.17–0.19 m/s in both groups, with overlapping confidence intervals. The authors cautioned, however, that the individual variability (coefficient of variation approximately 9–11%) was large enough that group-derived zones could misclassify intensity by 5–10% 1RM for a given individual.

In the back squat, findings are more nuanced. Balsalobre-Fernández et al. (2018) reported similar group-level LV relationships between male and female resistance-trained athletes, with velocity at 80% 1RM clustering around 0.52–0.58 m/s for both sexes. Critically, the between-individual spread was larger in females (SD ≈ 0.08 m/s) than in males (SD ≈ 0.05 m/s) in their cohort. Whether this reflects true sex differences in neuromuscular characteristics or simply greater heterogeneity in training history among female participants — who remain underrepresented in VBT research — is unclear from currently available data.

The provisional conclusion supported by the evidence is that sex alone does not reliably predict a meaningfully different velocity at a given %1RM. Population-level LV reference values from male cohorts are an imperfect but workable starting point for female athletes. The practical limitation is the same as it is for males: individual variation around group means is large enough that individualized profiling remains superior to any lookup table.

The minimal velocity threshold (MVT) — the mean concentric velocity at which an athlete can just barely complete a 1RM — is a critical parameter for LV profile-based 1RM estimation. If a practitioner uses the wrong MVT as the extrapolation anchor, the resulting 1RM estimate will be systematically off. The commonly cited MVT for the back squat is approximately 0.30 m/s and for the bench press approximately 0.15 m/s, values derived largely from male cohorts.

Evidence on whether females have systematically different MVTs is limited but instructive. Pareja-Blanco et al. (2020) reported that MVT in the back squat averaged 0.29 m/s in male athletes and 0.26 m/s in female athletes in their sample — a small but potentially meaningful difference. The direction (females slightly lower) aligns with mechanistic reasoning: females on average have a higher proportion of slow-twitch muscle fibers and a greater capacity to maintain force at very low velocities, which could allow a successful 1RM lift at marginally lower MCV. However, the difference was not statistically significant in that study, and the 95% confidence intervals substantially overlapped.

More practically problematic than any sex effect is the large within-sex individual variation in MVT. Across exercises and cohorts, MVT has been shown to vary by as much as ±0.05–0.08 m/s between individuals of the same sex. Using a fixed MVT anchor (e.g., always 0.30 m/s for the squat) therefore introduces greater error than any sex-related adjustment could correct. The appropriate response is to measure each athlete's MVT directly — by performing an incremental loading test to true 1RM and recording the actual MCV at that load — rather than assuming a population average regardless of sex.

The following table summarizes the primary studies examining sex differences in load-velocity relationships and related VBT parameters. Note that female-specific samples remain underrepresented, and most mixed-sex studies were not originally designed to test sex as a primary variable.

A consistent theme across all four studies is that the magnitude of between-individual variability within each sex exceeds the magnitude of any systematic between-sex difference. This finding has a direct bearing on programming decisions: it argues more forcefully for individualized profiling than for sex-specific reference tables.

Velocity-loss percentage within a set — the drop in MCV from the first to the last rep — is used in VBT programming to regulate fatigue exposure. Common thresholds are 20% velocity loss for hypertrophy stimulus and 10% for power and velocity quality. An important but underexamined question is whether female athletes accumulate intra-set velocity loss at the same rate as males for equivalent %1RM loads and set structures.

The mechanistic case for sex differences in fatigue response is plausible. Research on neuromuscular fatigue has consistently demonstrated that females show less peripheral fatigue and slower force decrement during sustained or repeated contractions compared to males, even when controlling for strength level. This is attributed to several factors: relatively greater type I fiber density, lower absolute force production generating less compressive occlusion of intramuscular blood flow, and potentially different neuroendocrine responses to exercise stress. If these mechanisms translate to the resistance training context, female athletes might be expected to show less intra-set velocity loss at equivalent %1RM and rep ranges.

Direct evidence from VBT studies is sparse. What is available tentatively supports attenuated intra-set velocity loss in females. In bench press protocols at 75% 1RM for sets of 8 repetitions, female participants in mixed-sex VBT studies have tended to exhibit velocity loss 3–6 percentage points lower than male participants — a pattern consistent with the fatigue-resistance data but not yet robust enough to recommend sex-specific velocity-loss thresholds with confidence. The more defensible position is to treat velocity-loss thresholds as individually calibrated targets informed by observed within-set velocity behavior, with the expectation that some female athletes — particularly those with high type I fiber density or aerobic fitness — may warrant lower velocity-loss limits to achieve equivalent metabolic stimulus.

A practical monitoring approach is to track each athlete's velocity-loss rate (the MCV decline per rep across several training sessions) and use that individual baseline to set thresholds, rather than assuming a universal 20% or 10% cutoff applies equally across sexes and individuals.

Inter-set recovery — how quickly bar velocity returns to baseline following a working set — determines optimal rest period length and influences volume accumulation capacity. If female athletes recover more rapidly than males after equivalent relative-load sets, shorter rest periods may be appropriate without sacrificing velocity quality in subsequent sets.

The fatigue-resistance literature suggests that females do recover faster from high-force, short-duration efforts, though the magnitude of this effect varies considerably depending on contraction mode, load, and fitness level. In practical VBT terms, a useful indicator of readiness is comparing the first-rep MCV of a new set against the athlete's baseline profile value for that load. If MCV has returned to within 5% of baseline, the athlete is ready to proceed regardless of elapsed clock time.

This velocity-based readiness check is arguably more individualized and accurate than prescribing sex-specific rest periods, since it accounts for the actual recovery state rather than assuming a group average applies. It also avoids the error of prescribing shorter rest periods for female athletes as a blanket policy — an approach that could be appropriate for some individuals but counterproductive for others, particularly during heavy strength phases where phosphocreatine resynthesis and central nervous system recovery are the rate-limiting steps for all athletes regardless of sex.

The practical upshot of the evidence reviewed above is that widely used velocity zone tables — almost all of which were developed on predominantly male samples — are a reasonable starting framework but should not be applied as fixed prescriptions for female athletes. Specifically:

• Velocity zone starting points: Use published reference values (e.g., 0.75–1.00 m/s for 60% 1RM back squat) as initial estimates, then refine via an LV profile test within the first 2–3 training sessions with a new female athlete. The group-level tables are sufficiently accurate for load prescription within ±5% 1RM in most cases, but the individual correction improves this substantially.
• MVT calibration: Do not use a sex-adjusted MVT anchor. Measure each athlete's actual MVT by performing an incremental load test to true 1RM and recording the MCV at that load. Store this value and update it every 6–8 weeks or after any significant training phase transition.
• Velocity-loss thresholds: Begin with standard thresholds (10% for power, 20% for hypertrophy) and monitor within-set velocity trajectories over the first 3–4 weeks. Adjust downward if the athlete consistently achieves the threshold in fewer reps than expected, or upward if sets are ending prematurely relative to perceived effort and technical quality.
• Exercise specificity: The LV relationship is exercise-specific. A female athlete's squat and bench press profiles must be built and maintained independently. Do not extrapolate velocity zones from one exercise to another.

The overarching message from the current evidence base is not that female athletes require a separate set of velocity tables — it is that all athletes, regardless of sex, require individualized LV profiles to get the full benefit of VBT prescription. The sex-difference question has been useful precisely because it has exposed how poorly group-level reference values serve individuals at the extremes of the normal distribution.

The argument for individualized profiling is strongest for the following athlete populations, where deviation from group means is most likely: (1) highly trained female athletes whose strength levels are at or above the male average in the reference samples used to build published LV tables; (2) older female athletes (35+) in whom hormonal and neuromuscular changes may alter the LV slope; (3) female athletes returning from lower-limb injury, where asymmetrical neuromuscular recovery can produce different LV profiles in the injured versus uninjured limb; and (4) female athletes in weight-class sports who regularly compete in a dehydrated state, which has been shown to alter MCV at a given relative load.

Practically, individualized profiling requires only 10–15 minutes of testing time and four to six submaximal sets across the load range of 50–85% estimated 1RM. The resulting regression line provides velocity zones accurate to within 2–3% 1RM for that athlete on that day. When re-tested at regular intervals, the profile also serves as a sensitive readiness and tracking tool — a use case that applies equally to male and female athletes but may be especially valuable in female athletes given evidence that hormonal cycle phase can influence neuromuscular output and therefore shift the LV profile by 3–8% across the month.

Synthesizing the current evidence into actionable guidance for coaches working with female athletes using VBT:

1. Do not assume male-derived velocity zones are wrong for female athletes — the group-level LV relationships are broadly similar. Do assume they are imprecise for any individual, and build individual profiles early.
2. Measure MVT directly rather than using a population-average anchor value. This is the single largest source of error in LV-based 1RM estimation and applies to all athletes regardless of sex.
3. Monitor intra-set velocity loss rather than prescribing it from a lookup table. Female athletes may exhibit less velocity loss per rep at equivalent %1RM — use the first 2–3 weeks of data to establish that individual's loss rate before fixing a threshold.
4. Use first-rep MCV to gauge inter-set recovery rather than prescribing fixed rest periods by sex. A MCV within 5% of baseline indicates readiness; below that threshold, extend rest regardless of elapsed time.
5. Re-profile regularly. Across menstrual cycle phases, training blocks, and seasonal demands, a female athlete's LV profile will shift. Quarterly re-profiling at minimum — ideally monthly for high-performance athletes — keeps velocity zones calibrated to current capacity.
6. Avoid overgeneralization in both directions. The evidence does not support the conclusion that female athletes are categorically different in their VBT response, nor that they are identical to males. The honest summary is: similar on average, variable as individuals — the same conclusion that applies to every other population studied in VBT research to date.