Kinetic chain approach versus scapular proprioceptive neuromuscular facilitation as adjuncts to conventional rehabilitation in male amateur overhead athletes with scapular positional asymmetry: a randomized clinical trial

Scapular positional asymmetry may be associated with shoulder symptoms, impaired movement control, and reduced sport-specific performance in overhead athletes. Although kinetic chain approach (KCA) and scapular proprioceptive neuromuscular facilitation (PNF) are commonly used in rehabilitation, their comparative effects remain unclear. This study compared the effects of adding kinetic chain exercises or scapular PNF to the same conventional rehabilitation program. In this randomized clinical trial, 22 male amateur overhead athletes aged 18–30 years (16 volleyball and 6 basketball players) with symptomatic shoulder pain and clinically defined scapular positional asymmetry were allocated to 4 weeks of conventional rehabilitation combined with KCA ( n = 11) or scapular PNF ( n = 11). The prespecified primary outcomes were the three directional reach scores and composite score of the Upper Quarter Y-Balance Test (UQYBT). Secondary outcomes included pain, active shoulder range of motion, scapular positional asymmetry measured by the lateral scapular slide test, upper-limb disability, throwing accuracy and power, and lower-quarter dynamic balance. Group, time, and group × time interactions were analyzed using 2 × 2 mixed-design analysis of variance, with a prespecified Bonferroni correction applied to all group × time interaction tests. The group × time interaction was significant for UQYBT medial reach, with greater improvement in the KCA group ( P < 0.001, ηp² = 0.762). However, the interaction was not significant for the UQYBT composite score ( P = 0.055, ηp² = 0.172), and no significant interactions were observed for the other UQYBT reach directions. Group × time interactions favored KCA for the LQYBT posteromedial, posterolateral, and composite scores ( P < 0.001 for all; ηp² = 0.642, 0.534, and 0.761, respectively). The anterior reach interaction was significant under the prespecified Bonferroni criterion ( P < 0.001) and remained significant in the Holm–Bonferroni sensitivity analysis (adjusted P = 0.007). In contrast, the interaction for pain favored PNF, indicating greater pain reduction in this group ( P < 0.001, ηp² = 0.502). No significant group × time interactions were found for shoulder range of motion, scapular positional asymmetry, disability, or throwing power. Among male amateur overhead athletes with symptomatic shoulder pain and clinically defined scapular positional asymmetry, KCA resulted in greater improvement than PNF in UQYBT medial reach. Overall, the two adjunctive rehabilitation approaches demonstrated outcome-specific effects rather than consistent superiority of one intervention. PNF was associated with greater short-term pain reduction, whereas KCA was associated with greater improvements in selected measures of dynamic balance and throwing accuracy. These findings should be interpreted cautiously because of the small sample size, the absence of a conventional-rehabilitation-only control group, and the lack of follow-up. Registered at IRCT (IRCT20230125057229N1; February 17, 2023).