A generation ago, many coaches discouraged athletes from lifting weights for fear that it would make athletes slow, inflexible, and “muscle-bound.” Thankfully, those days are (mostly) behind us, but there is still some conflicting research on the impact of resistance training on joint range of motion. Back in Volume 2 of MASS, Dr. Zourdos reviewed a study concluding that shoulder range of motion may be reduced in powerlifters compared to non-lifters (2). A recent study by Spence and colleagues (reviewed in this Research Spotlight) had similar findings (1). However, a 2021 meta-analysis (also reviewed in MASS) on longitudinal studies found that resistance training actually increases range of motion; in fact, resistance training seems to be just as effective as stretching for improving range of motion (3). So, how do we reconcile these (seemingly) conflicting findings?
The presently reviewed study (1) included 12 competitive male powerlifters and 13 recreationally strength-trained men. Researchers assessed squat and bench press 1RMs, and active range of motion at the shoulder, hip, and knee via goniometry. The researchers also pulled the powerlifters’ best meet results from the OpenPowerlifting database. They compared joint range of motion between the powerlifters and recreationally trained subjects, and assessed the correlations between range of motion and Wilks scores in the full sample (using the squat and bench press strength assessments performed during the study), and within the sample of powerlifters (using the subjects’ best meet results).
The powerlifters had less active shoulder extension and shoulder horizontal abduction range of motion than the recreationally trained lifters. They also had less hip flexion, hip extension, and hip adduction range of motion. Within the full sample, the researchers found that Wilks scores were negatively correlated with shoulder extension, shoulder horizontal abduction, hip flexion, hip extension, hip adduction, and hip internal rotation ranges of motion. In other words, smaller ranges of motion were predictive of greater relative strength. Within the sample of powerlifters, Wilks scores were negatively correlated with shoulder extension, shoulder horizontal adduction, shoulder horizontal abduction, hip flexion, and knee extension ranges of motion.
So, how can we interpret these results?
As I see it, there are two possibilities. The first is that long-term resistance training does decrease range of motion in some joints, and the second is that people with naturally less shoulder and hip range of motion are particularly well-suited for powerlifting.
While I think the first explanation is more plausible, I don’t want to completely discount the second possibility. If the bottom position in the bench press is closer to end-ROM for your pecs, and the bottom position in the squat is closer to end-ROM for your hip extensors, it’s possible that greater contributions from passive muscle tension could help you move slightly heavier loads off your chest or out of the bottom position of a squat. However, I doubt that such a relationship explains anywhere near 40% of the variance in strength between individuals (the approximate R2 value for the relationships between Wilks scores and both shoulder flexion and horizontal abduction range of motion).
I think the more plausible explanation is that long-term resistance training truly can decrease range of motion at some joints. However, I think the most likely mechanism underpinning this reduction in range of motion isn’t what most people would expect. Some people are concerned that strength training reduces range of motion by making you “tight,” but I think it’s more plausible that strength training reduces range of motion by making you jacked. And, in fact, the negative correlations between ranges of motion and Wilks scores provide indirect evidence for this explanation.
Clearly the more muscle you have, the more space it occupies. For certain joints and muscles, it’s obvious that having more muscle can limit range of motion. For example, if you have enormous biceps and forearms, your elbow flexion range of motion will be limited compared to someone with substantially less muscle. Range of motion isn’t limited because you’re “tight” – it’s limited because there’s a lot of finitely-compressible tissue between your forearm and humerus. I think similar principles explain most of the correlations between range of motion and Wilks score in the present study. Try out some active range of motion tests for shoulder and hip extension. When you perform these tests, what do you feel? When I perform the shoulder extension test, my lats start cramping long before I feel a stretch in my anterior deltoids or biceps, and when I perform the hip extension test, I don’t feel a hip flexor stretch – it just feels like I reach a point where my glutes simply can’t contract anymore. The same general principle applies to shoulder horizontal abduction (you’ll probably your rear delts and traps reach the point where they can’t contract anymore before your pecs feel a stretch) and hip adduction (it’s hard to go into a ton of hip adduction if huge adductors are taking up a lot of space).
Put simply, I think that many of these tests are rough proxies for muscularity, and muscularity is a strong predictor of powerlifting performance. Thus, it would make sense that limited range of motion in some joints is associated with superior powerlifting performance: lifters aren’t performing better because they’re “tight”; they perform better because they’re jacked, and their range of motion is also limited because they’re jacked.
As further indirect evidence for this explanation, the same research group found that range of motion was similar in female powerlifters and recreationally trained female lifters (4). Although relative rates of hypertrophy and strength gains are similar between the sexes, male lifters have considerably more muscle mass on an absolute basis. If heavy training simply made lifters “tight,” you’d expect female powerlifters to also possess reduced ranges of motion. However, if a certain level of muscularity inhibits ranges of motion due to finite tissue compressibility (rather than extensibility), it’s entirely possible that most female powerlifters simply don’t achieve absolute levels of muscularity that are sufficient to reduce ranges of motion.
This explanation also helps reconcile the present findings with the seemingly-contradictory meta-analysis, which found that resistance training increases range of motion (3). Keep in mind that most of the studies in that meta-analysis used untrained subjects. I’m proposing that resistance training increases tissue extensibility, which increases range of motion to a point; however, once you accumulate enough muscle mass, the muscle mass itself can limit range of motion in some joints, regardless of tissue extensibility. As a corollary, these reductions in range of motion should be the most notable in active range of motion tests, because active range of motion tests require you to contract the muscles on the back side of the joint being assessed. When muscles actively contract, they become harder, and their compressibility decreases. I suspect that the range of motion differences between powerlifters and recreational lifters would be considerably smaller in passive range of motion tests.
To be clear, my proposed explanation isn’t the only possibility. Shoulder injuries are fairly common in powerlifters (5). So, perhaps stronger powerlifters have been training for longer than weaker powerlifters and recreational lifters, they’ve accumulated both strength and injuries over time, and their injuries reduce their shoulder extension and horizontal abduction range of motion. However, I don’t find this explanation particularly plausible; it would imply that prior injuries (that reduce joint range of motion long-term) are positively associated with competitive success, which doesn’t match my experience in the sport. It’s also possible that strength training initially increases tissue extensibility in untrained lifters, but then it reduces tissue extensibility over time. However, without a mechanism to explain such a reversal, that explanation also doesn’t seem particularly plausible. So, pending further research, I think the most likely explanation for these results is simply that more muscular powerlifters are generally more successful powerlifters, and sheer muscularity can limit your active range of motion for certain joint actions, independent of “tightness.”
Note: This article was published in partnership with MASS Research Review. Full versions of Research Spotlight breakdowns are originally published in MASS Research Review. Subscribe to MASS to get a monthly publication with breakdowns of recent exercise and nutrition studies.
- Spence A-J, Helms ER, Sousa CA, McGuigan MR. Range of Motion Predicts Performance in National-Level New Zealand Male Powerlifters. Journal of Strength and Conditioning Research: January 5, 2022 – Volume – Issue – doi: 10.1519/JSC.0000000000004205
- Gadomski SJ, Ratamess NA, Cutrufello PT. Range of Motion Adaptations in Powerlifters. J Strength Cond Res. 2018 Nov;32(11):3020-3028. doi: 10.1519/JSC.0000000000002824. PMID: 30204657.
- Afonso J, Ramirez-Campillo R, Moscão J, Rocha T, Zacca R, Martins A, Milheiro AA, Ferreira J, Sarmento H, Clemente FM. Strength Training versus Stretching for Improving Range of Motion: A Systematic Review and Meta-Analysis. Healthcare (Basel). 2021 Apr 7;9(4):427. doi: 10.3390/healthcare9040427. PMID: 33917036; PMCID: PMC8067745.
- Spence AJ, Helms ER, McGuigan MR. Range of Motion Is Not Reduced in National-Level New Zealand Female Powerlifters. J Strength Cond Res. 2021 Oct 1;35(10):2737-2741. doi: 10.1519/JSC.0000000000004117. PMID: 34334773.
- Aasa U, Svartholm I, Andersson F, Berglund L. Injuries among weightlifters and powerlifters: a systematic review. Br J Sports Med. 2017 Feb;51(4):211-219. doi: 10.1136/bjsports-2016-096037. Epub 2016 Oct 4. PMID: 27707741.