At-home resistance tubing strength training increases shoulder strength in the trained and untrained limb

The purpose was to determine if an at-home resistance tubing strength training program on one shoulder (that is commonly used in rehabilitation settings) would produce increases in strength in the trained and untrained shoulders via cross-education. Twenty-three participants were randomized to TRAIN (strength-trained one shoulder; n=13) or CONTROL (no intervention; n=10). Strength training was completed at home using resistance tubing and consisted of maximal shoulder external rotation, internal rotation, scaption, retraction, and flexion 3 days/week for 4 weeks. Strength was measured via handheld dynamometry and muscle size measured via ultrasound. For external rotation strength, the trained (10.9 +/- 10.9%) and untrained (12.7 +/- 9.6%) arm of TRAIN was significantly different than CONTROL (1.6 +/- 13.2%; -2.7 +/- 12.3%; pooled across arm; P<0.05). For internal rotation strength, the trained (14.8 +/- 11.3%) and untrained (14.6 +/- 10.1%) arm of TRAIN was significantly different than CONTROL (6.4 +/- 11.2%; 5.1 +/- 8.8%; pooled across arm; P<0.05). There were no significant differences for scaption strength (P=0.056). TRAIN significantly increased muscle size in the training arm of the supraspinatus (1.90 +/- 0.32 to 1.99 +/- 0.31cm), and the anterior deltoid (1.08 +/- 0.37 to 1.21 +/- 0.39cm; P<0.05). This study suggests that an at-home resistance tubing training program on one limb can produce increases in strength in both limbs, and has implications for rehabilitation after unilateral shoulder injuries.