The relationship between exposure to long-term training, neuromuscular function and muscular structure in adolescents with cerebral palsy and typically-developed peers: a cross-sectional follow-up analysis

Background This cross-sectional study examined whether exposure to long-term resistance and endurance training can counteract muscular weakness on a functional, neurological and structural level in adolescents with cerebral palsy (CP) compared with typically-developed peers (TD) in dependence of training status. Methods Five trained (4 males; mean age: 19.8) and four untrained adolescents with CP (3 males; 20.2) were compared with nine age- and sex-matched TD trained (7 males; 19.8) and nine untrained TD peers (7 males; 20.3). Isometric and isokinetic measurements assessed strength in knee flexion and extension, voluntary activation (VA) was assessed by the twitch interpolation technique and ultrasound imaging of the m. quadriceps was performed to assess anatomical cross sectional area (ACSA). Both legs were assessed in all participants. Results CP trained showed lower absolute isometric strength (dominant: -18% [-48; 11]; non-dominant: -35% [-58; -11]) than TD untrained while CP untrained showed between 29% and 33% lower strength than TD untrained. VA in CP trained (dominant: -13% [-23; -3]; non-dominant: -10% [-30; 11]) and CP untrained (dominant: -14% [-23; -4]; non-dominant: -8% [-29; 13]) showed similar deficits compared with TD untrained. CP trained showed higher ACSA than TD untrained in the dominant leg of the m. vastus lateralis (+ 16% [-7; 38]), while the non-dominant side showed lower values (-18% [-45; 9]). Conclusion Exposure to long-term resistance and endurance training is associated with a smaller gap in maximum strength and muscle volume in the dominant leg of adolescents with CP while neural drive does not seem to be affected by training exposure. Trial registration ClinicalTrials.gov Identifier NCT05859360 / Registration date May 4, 2023