Abstract
Background High‐speed resistance training has been shown to be a viable intervention for reducing neuromuscular symptoms in older persons with Parkinson's disease. Velocity‐based training, a recently developed resistance training modality, utilizes velocity rather than load to dictate progressions. No study has examined the effects of this training method on muscle structure in Parkinson's patients. Methods Sixteen older adults with Parkinson's disease (Hoehn and Yahr Stages 1–3) were randomly assigned to a 10% (n = 7, 6 males, 1 female) or 30% (n = 9, 6 males, 3 females) velocity loss threshold protocol twice weekly for 12 weeks of velocity‐based training. Changes in ultrasound measures including muscle thickness, echo intensity, pennation angle, shear wave elastography, and performance measurements including specific force and power of the left and right rectus femoris and vastus lateralis were analysed before and after the intervention period. Results Significant improvements were seen for the sample in muscle thickness for the right (MDiff ± SE = 0.19 ± 0.05 cm; p = 0.003) and left (0.20 ± 0.09 cm; p = 0.033) rectus femoris and the right (0.14 ± 0.06 cm; p = 0.04) and left (0.19 ± 0.07 cm; p = 0.018) vastus lateralis. For echo intensity, there were significant improvements for the right rectus femoris (−3.37 ± 1.29 units; p = 0.002) and the left vastus lateralis (−7.11 ± 2.68 units; p = 0.019); however, improvements in the left (p = 0.033) and right (p < 0.001) vastus lateralis were seen only by the 30% velocity loss threshold group. Significant increases in pennation angle were detected in the right rectus femoris (2.47° ± 0.84°; p = 0.011) and reductions in shear wave elastography for the left rectus femoris (−3.33 ± 1.29 kPa; p = 0.013) of the sample. For specific power, significant improvements were seen for the right (0.02 ± 0.01 W·cm3; p = 0.040) and left (0.04 ± 0.02 W·cm3; p = 0.047) rectus femoris muscles for both groups. Conclusions Results indicate that 12 weeks of velocity‐based training can produce positive changes in muscle morphology and neuromuscular performance of the lower limbs for individuals with Parkinson's disease. Furthermore, using a 30% velocity loss threshold is more effective than using a 10% velocity loss threshold. Trial Registration: 20220489