Structural changes in the muscle-tendon complex of triceps surae after a daily self-stretch program in chronic hemiparesis: A one-year randomized controlled trial

Abstract

The effects of long-term (> 6 months) stretching in spastic paresis are unknown. The objective of this study was to compare the architectural and clinical changes in plantar flexors in patients with chronic hemiparesis following a one-year daily self-stretch program vs. standard rehabilitation. Twenty-three patients with chronic hemiparesis (8 W; mean age, 56 [12]; time since lesion 9 [8]) participated in a one-year randomized controlled trial involving either conventional therapy (CONV) or a daily self-stretch program within a Guided Self-rehabilitation Contract (GSC). Assessments involved: (i) soleus and medial gastrocnemius (MG) fascicle length, pennation angle, thickness, tendon length, measured by ultrasonography; (ii) XV1, angle of arrest at slow stretch in soleus (XV1SOL), gastro-soleus complex (XV1GAS), gluteus maximus (XV1GM) and rectus femoris (XV1RF); (iii) 10-meter maximal ambulation speed. Correlations (Pearson's) between architectural parameters and XV1 were also explored. After one year, soleus fascicle length increased by +16.6 mm (CI95 [+10.3; +22.9]; +42%), in the GSC group vs. −0.1 mm (CI95 [−7.3; +7.1]; −3.7%), in the CONV group ( P = 0.005, Rank-Ancova), MG fascicle length increased by +5.2 mm (CI95 [+2.75; +7.65]; +13%), in the GSC group vs. +1.2 mm (CI95 [−2.0; +4.4]; +7%), in the CONV group ( P = 0.01), soleus thickness increased by +4.3 mm (CI95 [+2.7; +5.9]; +33%), vs. −0.3 mm (CI95 [−2.4; +1.8]; −0.8%), in the CONV group ( P = 0.005). Changes in XV1 involved XV1SOL, +2.4° (CI95 [+0.9; +4.0]; +2.4%), in the GSC group vs. +0.1° (CI95 [−2.7; +2.8]; +0.1%), in the CONV group ( P = 6.9 E-05); XV1GAS, +7.4° (CI95[+5.0; +9.8]; +8%) vs. +1.5° (CI95 [−3.3; +6.3]; +1.5%; P = 0.003); XV1GM, +5.3° (CI95[+2.7; + 7.9]; 4.2%) vs. +1.5° (CI95[+0.1; +5.4]; +1.2%; P = 0.025); XV1RF, +10.5° (CI95 [+5.8; + 16.4]; +3.4%) vs. +1.5° (CI95 [−3.75; +6.65]; +1.9%; P = 0.08). Walking speed increased by +0.08 m/s (CI95 [+0.04; +0.12]; +14%, P = 0.006, t -test) in the GSC group vs. +0.04 m/s (CI95[0.0; +0.08]; +5%, NS) in the CONV group. At baseline, XV1SOL correlated negatively with soleus tendon length ( R = −0.74, P = 0.0003) and positively with muscle thickness ( R = 0.68, P = 0.015). In patients with chronic hemiparesis, a daily self-stretch program of soleus and medial gastrocnemius through Guided Self-rehabilitation Contract over one year increased muscle fascicle length and thickness more than conventional rehabilitation.