How much strength is “strong enough” for speed?
A brief review of relative strength, sprint performance, and where the curve may flatten
The relationship between lower-body strength and sprint performance is one of the most established ideas in strength and conditioning, but the applied question is more specific: how much strength is actually enough to meaningfully support speed? (McBride et al., 2009; Seitz et al., 2014) Coaches rarely need to know whether stronger athletes are generally faster; they need to know when continued investment in maximal strength is still likely to improve sprinting, and when the return on that investment begins to fall (Van Hooren et al., 2024; Vial et al., 2022; Wagner et al., 2023). That is the practical problem behind the phrase “strong enough.”
A useful way to frame that problem is through relative strength, usually expressed as maximal force capacity in relation to body mass (Wagner et al., 2023). For sprinting, this matters because the athlete is not simply producing force against an external object; they are accelerating their own body mass over very short ground-contact times (Haugen et al., 2019; Van Hooren et al., 2024). As a result, absolute strength alone can be misleading. Two athletes may squat similar loads, but if one carries substantially less non-functional mass, that athlete may have the better sprint profile (Van Hooren et al., 2024; Wagner et al., 2023).
Older studies established a consistent association between relative lower-body strength and sprint performance, particularly over short acceleration distances (McBride et al., 2009; Seitz et al., 2014). Newer studies broadly support that relationship, but they also suggest the curve is not perfectly linear forever (Comfort et al., 2024; Vial et al., 2022; Wagner et al., 2023). Once athletes reach a certain level of relative force production, further increases in maximal strength appear to have a smaller and more inconsistent transfer to speed, while other qualities such as rapid force production, reactive strength, and sprint-specific mechanics become more influential (Comfort et al., 2024; Vial et al., 2022; Van Hooren et al., 2024) This brief review examines that transition from “get stronger” to “strong enough.”
Relative strength as the practical lens
In applied settings, relative strength is often operationalised through measures such as back squat one-repetition maximum divided by body mass, or similar lower-body force metrics normalised to body mass (McBride et al., 2009; Vial et al., 2022; Wagner et al., 2023). This is not merely a statistical preference. Sprinting requires the athlete to generate high external force while simultaneously overcoming inertia and repeatedly repositioning their own system mass (Comfort et al., 2024; Van Hooren et al., 2024). From that perspective, the strength that matters is not simply how much force can be produced in absolute terms, but how much usable force is available per kilogram of body mass (Van Hooren et al., 2024; Wagner et al., 2023).
This distinction helps explain why relative strength has shown more consistent relationships with sprint outcomes than absolute strength across a range of athletic populations (McBride et al., 2009; Wagner et al., 2023). In trained field-sport athletes, stronger correlations are typically seen between sprint performance and body-mass-adjusted strength metrics than with raw 1RM values alone (McBride et al., 2009; Wagner et al., 2023). For the coach, this matters because an athlete can improve an absolute squat number without meaningfully improving the quality that sprinting actually depends on (Van Hooren et al., 2024; Wagner et al., 2023). In some cases, especially when mass gain accompanies strength gain, absolute improvement may even mask a plateau in usable speed-related force capacity (Osses-Rivera et al., 2024; Van Hooren et al., 2024).
What older studies established
One of the most widely cited foundational papers is McBride et al. (2009), who examined the relationship between maximal squat strength and 5-, 10-, and 40-yard sprint times in Division I-AA American football players. The authors reported significant negative correlations between relative squat strength and sprint times at 10 and 40 yards, indicating that athletes with higher squat-to-body-mass ratios tended to sprint faster (McBride et al., 2009). The study also divided athletes into stronger and weaker groups, showing that those above roughly 2.10 times body mass were significantly faster than those below 1.90 times body mass over 10 and 40 yards (McBride et al., 2009). Although the sample was small and the study was cross-sectional, it became influential because it translated a broad principle into a usable coaching heuristic: around two times body mass in the squat seemed to matter (McBride et al., 2009).
A second major reference point is the meta-analysis by Seitz et al. (2014), which found that increases in lower-body strength transferred positively to sprint performance, with a large relationship between improvements in squat strength and changes in sprint times. Their analysis reinforced the view that strength development is a viable route to improved speed, particularly in athletes who are not yet highly developed (Seitz et al., 2014). Importantly, however, the meta-analysis did not establish a firm ceiling. It showed that strength gains can improve sprinting, but not that they always continue to do so to the same extent as athletes become stronger (Seitz et al., 2014).
Applied intervention studies in team-sport settings also helped to shape the field. For example, research in professional soccer players has shown that increases in squat strength during short in-season training periods can coincide with small but significant improvements in 5- to 20-m sprint performance (Styles et al., 2016). These studies were valuable because they demonstrated transfer in realistic performance environments, not just in isolated strength assessments (Styles et al., 2016). At the same time, most older intervention studies involved athletes whose relative strength levels were still moderate rather than exceptional, which limits how confidently they can answer the “strong enough” question at higher levels of development (Seitz et al., 2014; Styles et al., 2016).
Overall, the older literature established three points reasonably well. First, stronger athletes generally sprint faster, especially during acceleration (McBride et al., 2009; Seitz et al., 2014). Second, relative strength appears more informative than absolute strength (McBride et al., 2009). Third, building lower-body strength is a sensible strategy for improving speed, particularly in weaker or less trained populations (Seitz et al., 2014; Styles et al., 2016). What those studies did not fully resolve was whether the relationship stays linear at higher levels of performance or whether the curve begins to flatten (McBride et al., 2009; Seitz et al., 2014).
What newer studies add
More recent work has refined the discussion in two main ways. First, newer studies have more consistently distinguished between absolute and relative strength (Comfort et al., 2024; Wagner et al., 2023). Second, some have begun to model non-linear behaviour directly rather than assuming the relationship is linear throughout (Vial et al., 2022).
Wagner et al. (2023) examined the relationships between absolute and relative maximal strength measures and speed-power tasks in trained team-sport athletes Their findings showed that relative maximum strength displayed clearer and stronger associations with sprint performance than absolute strength, with moderate to large correlations across short sprint distances (Wagner et al., 2023). This is important because it confirms that the body-mass-adjusted view of force production remains relevant even in trained populations, not just in novice athletes (Wagner et al., 2023). However, the study still largely describes associations rather than exact breakpoints, so it helps confirm what matters more than where the plateau begins (Wagner et al., 2023).
Another newer contribution is the growing interest in rapid force production. A 2024 paper reported that relative strength explained a substantial proportion of differences in multi-joint rapid force output between athletes, suggesting that maximal strength still provides an important foundation for explosive expression (Comfort et al., 2024). Yet the study also implies that maximal strength does not explain everything once athletes reach reasonably high levels. (Comfort et al., 2024). In other words, stronger athletes usually retain an advantage, but the ability to produce force quickly becomes a more discriminating factor as maximal strength rises (Comfort et al., 2024; Van Hooren et al., 2024).
The clearest recent evidence for a plateau-type phenomenon comes from Vial et al. (2022), who assessed football players using a battery that included isometric mid-thigh pull, Nordic hamstring strength, countermovement jump, standing broad jump, and 20- and 40-m sprint performance. Using random forest regression and partial dependence plots, the study identified a relative isometric strength value of approximately 2.0 times body mass as a saturation point, beyond which additional increases contributed little to explaining faster sprint times (Vial et al., 2022). Although isometric mid-thigh pull is not the same test as a back squat, the threshold discovered by Vial et al. (2022) is strikingly consistent with the practical zone long implied by McBride et al. (2009). That convergence is useful because it suggests the “around two times body mass” idea is not merely an artefact of one older study, but may reflect a broader transition point in force-oriented speed development (McBride et al., 2009; Vial et al., 2022).
A systematic review published in 2024 on strength training and repeated sprint ability in team-sport players adds another layer to the discussion (Osses-Rivera et al., 2024). Across controlled trials, the review found that strength training and complex or contrast training can improve best time, mean time, and total time in repeated sprint tests, especially when heavy loads or maximal power ranges are used (Osses-Rivera et al., 2024). However, the improvements were not universal, and some studies in already trained athletes showed modest or inconsistent gains (Osses-Rivera et al., 2024). This does not mean strength is no longer useful, but it does suggest that once a reasonable strength base is in place, more strength alone may not be the most efficient route to better sprint performance in all contexts (Osses-Rivera et al., 2024).
Newer narrative syntheses have taken a similar view. Recent reviews on resistance training for sprint performance argue that maximal strength is best understood as a foundational quality that enables speed development up to a point, after which the limiting factors become more specific to sprint execution (Van Hooren et al., 2024). Those factors include rapid force expression, stretch-shortening cycle efficiency, horizontal force orientation, and technical coordination (Haugen et al., 2019; Van Hooren et al., 2024). This is a more nuanced conclusion than the simple idea that increasing a squat 1RM will always continue to improve speed (Van Hooren et al., 2024).
Where the curve seems to flatten
The current evidence does not support a single universal threshold for all athletes, sports, or testing methods (Van Hooren et al., 2024; Vial et al., 2022; Wagner et al., 2023). Even so, a practical pattern has emerged. Across older and newer studies, relative force values around 2.0 times body mass repeatedly appear as a meaningful zone for sprint-related performance (McBride et al., 2009; Vial et al., 2022). In McBride et al. (2009), athletes above about 2.10 times body mass in the squat were faster than those below 1.90 times body mass. In Vial et al. (2022), the saturation point for a relative isometric strength measure appeared at approximately 2.0 times body mass. While these are not identical tests, they point in a similar direction.
That does not mean the relationship becomes flat overnight at that number (Van Hooren et al., 2024; Wagner et al., 2023). It is better understood as a shift in slope: as weaker athletes get stronger, sprint gains are usually more obvious; as stronger athletes become even stronger, the same increase in force capacity tends to produce a smaller gain in sprint speed (Seitz et al., 2014; Van Hooren et al., 2024; Vial et al., 2022). Put differently, the curve appears to move from clearly productive to increasingly inefficient rather than from useful to useless (Van Hooren et al., 2024; Vial et al., 2022).
This interpretation fits both training theory and the newer evidence base. If an athlete is far below a robust strength standard, maximal force production may be a primary limiter (Seitz et al., 2014; Van Hooren et al., 2024). Once that athlete reaches a higher relative strength level, other constraints begin to dominate, and the next 10 kg on the bar may matter less than the next improvement in horizontal impulse, contact quality, or sprint technique (Comfort et al., 2024; Van Hooren et al., 2024; Vial et al., 2022).
Why the relationship stops being purely linear
There are several plausible reasons why maximal strength loses explanatory power at higher levels. The first is time. Sprinting occurs under very brief ground-contact durations, particularly as velocity rises (Haugen et al., 2019; Van Hooren et al., 2024). Maximal squat strength reflects force capability under much slower conditions, whereas sprinting increasingly depends on how much force can be expressed within a very small time window (Comfort et al., 2024; Van Hooren et al., 2024). Once athletes are already strong, differences in rate of force development and reactive strength may become more decisive than differences in maximal force alone (Comfort et al., 2024; Van Hooren et al., 2024).
The second reason is specificity of force orientation. Bilateral squatting is largely vertical, while sprint acceleration and maximal velocity depend heavily on the capacity to direct force effectively in the horizontal plane and coordinate that force across stride cycles (Haugen et al., 2019; Van Hooren et al., 2024). This helps explain why stronger athletes may still plateau if their training continues to improve general force capacity without improving how that force is expressed in sprinting itself (Van Hooren et al., 2024).
The third reason is body mass trade-off. In some cases, chasing higher squat numbers comes with hypertrophy that does not improve sprint-specific force expression sufficiently to justify the extra mass (Osses-Rivera et al., 2024; Van Hooren et al., 2024). When that occurs, absolute strength may improve while relative strength stagnates, or relative strength may improve slightly without a corresponding gain in movement efficiency (Van Hooren et al., 2024; Wagner et al., 2023). This is especially relevant in field sports where acceleration, repeatability, and agility matter as much as collision capacity (Osses-Rivera et al., 2024).
Practical implications for coaches
From an applied point of view, the literature supports a staged interpretation rather than a one-size-fits-all prescription (Seitz et al., 2014; Van Hooren et al., 2024; Wagner et al., 2023) For athletes with relatively low strength, improving lower-body force capacity is still one of the clearest and most evidence-supported ways to improve sprint performance (Seitz et al., 2014; Styles et al., 2016). In this phase, getting stronger is usually not overcomplicated: the athlete likely needs more high-quality force production, and the transfer to short sprinting is often worthwhile (Seitz et al., 2014).
As the athlete approaches a more robust relative strength profile, roughly around the two-times-body-mass region in squat-like or isometric measures, the coach should become more critical about return on investment (McBride et al., 2009; Vial et al., 2022). If sprint times continue to improve meaningfully alongside strength gains, the programme is probably still solving the right problem (Vial et al., 2022; Wagner et al., 2023). If strength numbers keep rising while sprint performance changes little, it is increasingly likely that the limiting factor has shifted (Vial et al., 2022; Wagner et al., 2023).
At that point, the aim should not be to abandon strength work, but to reposition it (Osses-Rivera et al., 2024; Van Hooren et al., 2024). Maximal strength may move from being the primary driver of speed to being a maintained foundation that supports more sprint-specific interventions (Van Hooren et al., 2024). Training emphasis can then shift toward resisted and unresisted sprinting, plyometrics, reactive tasks, and technical work that improve horizontal force application and force expression under time pressure (Comfort et al., 2024; Osses-Rivera et al., 2024; Van Hooren et al., 2024). In practice, this means “strong enough” is not a reason to stop lifting; it is a reason to stop assuming that heavier lifting is the main answer (Van Hooren et al., 2024).
Conclusion
The combined weight of older and newer evidence supports a clear but qualified conclusion: relative lower-body strength is a major contributor to sprint performance, especially during acceleration, but its contribution is not endlessly linear (McBride et al., 2009; Seitz et al., 2014; Wagner et al., 2023). Older foundational studies established that stronger athletes are usually faster and helped popularise practical benchmarks near two times body mass in the squat (McBride et al., 2009; Seitz et al., 2014). Newer research largely confirms the value of relative strength while also indicating that around this region, the relationship begins to flatten and further gains become more dependent on how force is expressed rather than simply how much maximal force can be produced (Comfort et al., 2024; Van Hooren et al., 2024; Vial et al., 2022).
For coaches, the practical message is straightforward. Build relative strength aggressively in weaker athletes because it is likely to help speed (Seitz et al., 2014; Styles et al., 2016). Once athletes become sufficiently strong, monitor whether additional strength gains still improve sprint outcomes, and be prepared to redirect training toward more specific speed determinants when they do not (Van Hooren et al., 2024; Vial et al., 2022; Wagner et al., 2023). In that sense, “strong enough” is not a fixed law, but a decision point: the moment when the smartest next step is no longer just more force, but better use of it (Van Hooren et al., 2024).
References
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