Comparison Of Power Testing Strategies For Identifying Changes In Neuromuscularperformance In Persons With Parkinson’S Disease

For the past decade, resistance training (RT) has been used to improve power and associated functional deficits in persons with Parkinson’s Disease (PD). However, standardization of power testing methodologies using pneumatic resistance machines remains undetermined. PURPOSE: To determine the power testing methodologies that provide practitioners with meaningful assessments of improvements in maximum power and speed and across loads relative to a subject’s 1-repetition maximum (1RM). METHODS: 19 subjects with PD were randomized into either a traditional strength training (TST) or velocity-based training (VBT) condition for 12 weeks. Subjects completed power testing at 40, 50, 60, 70 and 80% of 1RM on both leg-press (LP) and chest-press (CP) prior to and following the training period. At post-test, testing was done twice using pre-test (PPpre) and post-test 1RM (PPpost) to compute power. RESULTS: After the 12-week period, separate 2 x 3 repeated measures ANOVAs revealed time effects for LP-PP (F (2,16) = 3.620, p = 0.050, ηp2 = .312) and CP-PP (F (2,15) = 6.242, p = 0.011, ηp2 = .454). Pairwise comparisons revealed a near significant change in LP-PPpre (MDiff ± SE = 50.58 ± 25.41 W; p = .063), and CP-PPpre (36.11 ± 10.0 W; p = .002) and CP-PPpost (47.39 ± 18.48 W; p = .021). A main effect for time was also seen for LP peak velocity (LP-PV) (F (2,16) = 5.668, p = 0.014, ηp2 = .415), with pairwise comparisons revealing significant improvements in LP-PVpre (3.36 ± 1.23; p = .014) that were significantly greater than those for LP-PPpost (1.61 ± .62; p = .019). No significant main effects or interactions were seen for CP-PV. A group x time analysis of pairwise comparisons revealed that significant LP-PPpre (79.05 ± 34.98 W; p = .037). and CP- PPpre (47.00 ± 14.14 m·s-1 ; p = .004) improvements seen in the VBT group alone. Similarly, a significant improvement was seen in LP-PVpre for the VBT group (4.00 ± 1.70 m·s-1 ; p = .031), which was significantly greater than the change observed in LP-PVpost (2.36 ± .85 m·s-1 ; p = .013). CONCLUSIONS: To better identify improvements in following training, power testing using pre-training 1RM values provides an analysis of change in power and velocity not constrained by increased loads associated with PPpost and PVpost. Further, a VBT intervention may prove superior to TST for improving PP and PV.