Author(s): RISVANG, L., BAUMGART, J.K., SANDBAKK, Ø., IRGENS, I., BOVIM, L.P., VAN DIJK, J.W., STRØM, V., RAASTAD, T., JONVIK, K.L., Institution: NORWEGIAN SCHOOL OF SPORT SCIENCES, Country: NORWAY, Abstract-ID: 2757

INTRODUCTION:
Adults who use wheelchairs often experience reduced upper-body strength and lean mass. While heavy resistance exercise is known to be effective in ambulatory populations, the long-term effects in wheelchair users remain unclear. We conducted a multi-centre, randomised controlled parallel-group study to investigate the effects of 24 weeks of high-load upper-body resistance exercise on changes in maximal muscle strength and lean mass.
METHODS:
Forty-five adults (40% female; 49% sports active; 18-60 years) using wheelchairs for ≥50% of mobility were allocated to high-load resistance exercise and nutrition optimisation (Training; n=24) or nutrition optimisation only (Control; n=21). The intervention comprised three weekly sessions of six upper body dynamic and isometric exercises, building up to ~75-90% 1RM after 4 weeks of conservative, supervised training. Linear mixed models assessed baseline-adjusted group differences at mid- (~12 weeks) and post-intervention (~25 weeks) based on intention-to-treat principles. Sensitivity analyses were performed excluding those in Training <80% attendance and Tukey’s rule defined outliers. Main outcomes were overhead and bench press 1RM and isometric voluntary contraction maximal strength, and lean soft tissue of the whole and upper body, and bilateral arms (dual-energy x-ray absorptiometry).
RESULTS:
Thirty-three participants completed the study. Compared with Control, Training showed greater improvements post-intervention in overhead and bench press 1RM (6.0 kg [2.1-9.9], p=0.006; 11.5 [5.7-17.4] kg, p<0.001), and in isometric overhead press and prone row (5.1 kg [1.0-9.1], p=0.024; 5.6 kg [0.5-10.6], p=0.048). No between-group differences were observed for total or upper body lean mass, whilst arms lean mass favoured Training marginally post-intervention (0.3 kg [0.0-0.5], p=0.050). Sensitivity analyses confirmed the robustness of results and changes in strength was associated with changes in lean mass.
CONCLUSION:
High-load resistance exercise over 24 weeks markedly improves upper-body maximal strength in adults who use wheelchairs, independent of changes in lean mass. These findings support the inclusion of heavy resistance training for this population. Further research is needed to determine optimal training programme design for wheelchair users.