Cross Education Training Effects are Evident with Twice Daily, Self-Administered Band Stretch Training

Currently there are recommendations for stretching type, repetitions and duration within a training session to improve flexibility. It is, however, unclear whether multiple daily stretch training sessions provide greater flexibility than single daily sessions. The objective was to investigate the effectiveness of single (1×day) versus twice daily (2×day) unilateral stretch training sessions on hip flexion range of motion (ROM), agonist and antagonist force and jump performance of the stretched and contralateral, non-stretched legs. Groups included a control, 1×day and 2×day stretch training groups. Static stretching (SS) involved self-administered (stretch band), unilateral, hamstrings and quadriceps stretching for 2-weeks. Pre- and post-testing involved hip flexion ROM, knee extension and flexion maximal voluntary isometric contraction (MVIC) forces and unilateral drop jumps (DJ). The 2×day group showed a 12.8% (p = 0.08) greater active ROM versus Control. The 1×day group showed a 7.5% (p=0.1) ballistic ROM increase with no significant changes with the 2×day and Control groups. The stretched leg experienced a 5.01% (p = 0.1) hip flexion ballistic ROM increase contrasting with a 2.3% increase for the contralateral leg. Twice daily training provided 7.1% (p = 0.07) and 6.6% (p = 0.01) quadriceps MVC force increases of the stretched trained and contralateral legs respectively. Contralateral DJ height improved 22.6% (p = 0.002) with 2×day training. In conclusion, 1xday and 2×day stretch training tended to improved ballistic and active ROM respectively, whereas 2×day training improved MVIC force and DJ height. The findings may apply to fitness enthusiasts and rehabilitation as unilateral stretching may retain performance and active ROM of the stretched and contralateral limbs.