科研之友
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摘要
Objectives: The tendon conditioning effect is transient, but the time course of recovery from conditioning is not known. This study examined the time-course recovery of three-dimensional (3D) Achilles tendon (AT) deformation immediately following a standardised AT conditioning protocol.
Design: Randomised crossover.
Methods: Ten healthy male adults (age: 24 +/- 5 years; height: 175.8 +/- 4.1 cm; body mass: 78.4 +/- 6.3 kg) attended the laboratory on 6 occasions. ATs were scanned using freehand 3D ultrasound during a 50% maximal voluntary isometric contraction (MVIC) of the plantarflexors immediately prior to and following the conditioning protocol (10 x 25 s plantarflexion contractions at 50% MVIC), and then at either 15, 30, 60, 90 or 120 min post-conditioning, randomised by session.
Results: Free AT longitudinal strain was significantly increased from 3.13 +/- 0.19% pre-conditioning to 7.49 +/- 0.20% immediately post-conditioning and was accompanied by a corresponding reduction in free AT transverse strain from -5.35 +/- 0.48% to -10.16 +/- 0.49% (p < 0.001). There were no significant differences in free AT longitudinal or transverse strains at 60 min relative to 0 min post-conditioning, or between pre-conditioning strains and strains measured at 2 h (p> 0.05).
Conclusions: The free AT undergoes a creep response during conditioning which is recoverable within 2 h following conditioning. Recovery from conditioning has the potential to be a source of error during in vivo measurement of AT mechanical properties. The time window in which the free AT longitudinal and transverse strains could be achieved without a large confounding effect of creep recovery is 0-60 min post-conditioning.
- 出版日期2018-5
