Limb Dominance Effects on Seated Single-Arm Shot-Put Limb Symmetry Indices Following Shoulder Rehabilitation

Abstract

Typically, most clinical return to activity guidelines recommend that an injured shoulder achieve a 90% to 100% functional performance test limb symmetry index (LSI); however, as previous research demonstrated a 103% to 111% dominant limb bias in seated single-arm shot-put test (SSASPT) performance, the typical criteria might not be appropriate for interpreting SSASPT LSI. Thus, the current objective was to evaluate SSASP LSI differences between dominant and nondominant involved shoulders and to determine how many patients met the suggested 90% to 100% LSI criteria, as well as the 103% for dominant (89% for nondominant) normative SSASPT threshold reported in the literature, at the time of discharge. Cross-sectional. Patients with shoulder injury or surgery (n = 78) completed the SSASPT at the time of discharge from rehabilitation and were grouped according to whether the involved shoulder was the dominant (n = 42) or nondominant (n = 32) limb. LSI (involved/uninvolved × 100) was computed from the average of 3 SSASPT trial distances completed with each limb. The LSI for the nondominant involved group (88.9% [12.4%]) was significantly less (confidence intervalDiff, -12.1% to -22.1%) than the dominant involved group (106.0% [9.3%]). While 95.2% of patients in the dominant involved group exhibited LSI > 90%, only 43.8% of patients in the nondominant involved group attained LSI > 90%. Across the entire cohort, the odds of a nondominant involved LSI being below the respective SSASPT normative range were 2.04 (95% confidence interval, 0.80-5.21) times higher than the odds of a dominant involved LSI being below the normative range. Patients with dominant limb involvement exhibited higher LSI than patients with nondominant limb involvement at discharge from rehabilitation. Particularly when the nondominant shoulder is involved, these results suggest that patients with shoulder injury and surgery may require longer rehabilitation to attain higher levels of upper-extremity function.