Strength profiles of shoulder rotators in healthy sport climbers and nonclimbers

To establish the isokinetic strength profiles and work ratios of the shoulder internal and external rotators in sport climbers and to compare them with these profiles and ratios in nonclimbers. We hypothesized that the strength profiles of the shoulder rotators were different between sport climbers and nonclimbers.

Cross-sectional study.

Exercise science laboratory.

Thirty-one experienced sport climbers and 27 nonclimbers.

We tested all participants by measuring the isokinetic concentric and eccentric work output of their shoulder rotators in the middle 110 degrees of shoulder rotation. We measured mean conventional work ratios of concentric external rotation (ER) to internal rotation (IR) (con ER:IR) and eccentric ER to IR (ecc ER:IR), and we measured mean functional work ratios of eccentric ER to concentric IR (ecc ER:con IR) and eccentric IR to concentric ER (ecc IR:con ER).

All work ratios were different between the 2 groups (P < .001). In the climbers, the conventional work ratios were smaller than 1 for con ER:IR (0.79) and ecc ER:IR (0.88), whereas for the nonclimbers, the ratios were 1.03 and 1.13, respectively. The functional work ratio of ecc ER:con IR was smaller for the climbers (1.05) than for the nonclimbers (1.30), but the functional work ratio of ecc IR:con ER was larger for the climbers (1.58) than for the nonclimbers (1.17).

The difference in work ratios of the shoulder rotators between participant groups might be due to training-induced changes in the shoulder rotation muscles of sport climbers. The clinical implication of this strength difference in shoulder IR and ER in climbers has yet to be examined.