Abstract
We previously reported increased running economy and joint range of motion (ROM) during subsequent exercise performed 48-h following strenuous exercise while wearing garments containing micro-titanium particles generated from high-pressure aqueous processing of titanium (AQUA TITAN(TM)). Here we utilised an isolated plantarflexion triceps surae model and AQUA TITAN-treated flexible tape to determine if dermal application of the micro-titanium could account for meaningful changes in functional properties of the musculotendinous unit. In a randomised double-blind crossover, 20 trained men day 1, baseline measures, AQUA TITAN or placebo tape covering the triceps surae, intermittent high-intensity treadmill running; day 2, rest; day 3, post-stress post-treatment outcome measures. Outcomes comprised: plantarflexion ROM via isokinetic dynamometry; short latency reflex from electromyography; Achilles tendon stiffness from isometric dynamometry, ultrasonography (Achilles-medial-gastrocnemius junction), motion analysis, and force-length modelling. High-intensity exercise with placebo tape reduced tendon stiffness (-16.5%; 95% confidence limits ±8.1%; small effect size), relative to non-taped baseline, but this effect was negligible (-5.9%; ±9.2%) with AQUA TITAN (AQUA TITAN-placebo difference -11.3%; ±11.6%). Change in latency relative to baseline was trivial with placebo (1.6%; ±3.8%) but large with AQUA TITAN (-11.3%; ±3.3%). The effects on ROM with AQUA TITAN (1.6%; ±2.0%) and placebo were trivial (-1.6% ±1.9%), but the small difference (3.1%; ±2.7%) possibly greater with AQUA TITAN. AQUA TITAN tape accelerated the reflex response and attenuated reduced Achilles tendon stiffness following fatiguing exercise. Altered neuromuscular control of tendon stiffness via dermal application of micro-titanium treated materials may facilitate restoration of musculotendinous contractile performance following prior strenuous exercise.