Publications

Purpose: Stretching is a common strategy to acutely improve range of motion (ROM). Underlying mechanisms typically involve stretch tolerance and reduced tissue stiffness. Alternatively, vibration training can be used to improve ROM which can be attributed to circulatory and neural mechanisms. While combining stretching with vibration yields small benefits in young and healthy adults, evidence in older adults is scarce. The objective was to investigate whether superimposing vibration on stretching provides acute ROM benefits compared to stretching alone on flexibility, muscle–tendon stiffness, and skin temperature.

Methods: Conducted as assessor-blinded, randomized cross-over study with three conditions, eight participants performed either stretching + vibration (ST + V), stretching alone (ST), and passive control (CG). ROM was evaluated via the passive straight-leg-raise and active sit-and-reach test. Biceps femoris and Achilles tendon stiffness were measured via myotonometry. Skin temperature was captured via infrared thermography.

Results: Both intervention conditions improved passive ROM by large effect sizes (d = 2.16–3.16, p < 0.001), but only ST + V enhanced active ROM (d = 1.23, p = 0.048). Vibration superimposition also significantly moderated viscoelastic parameters and maintained/elevated calf skin temperature, whereas temperature declined in ST and CG by moderate to high effect size. Achilles tendon stiffness decreased immediately after ST (d = − 1.24, p = 0.049) and 30 min after ST + V (d = − 1.64, p = 0.015).

Conclusion: Discussing the tonic vibration reflex as underlying mechanism, this study showed superimposed vibration increased active ROM and decreased stiffness. Although additional vibration could offer additional practical benefits for flexibility interventions in aging populations, the clinical relevance must be further investigated in larger populations.

Figure 1. Measurement procedure for Pre- and Post-Tests including infrared thermography (IRT), myotonometry (MyotonPRO) of biceps femoris and Achilles tendon, straight-leg-raise (SLR), stand-and-reach (S&R), and again IRT

Keywords: vibratory stimulation, range of motion, stiffness, myotonometry, infrared thermography, elderly

These results showed pronounced acute effects of additional vibration in combination with stretching concerning active ROM, skin temperature and viscoelastic parameters in older adults. Although the small sample size might negatively impact the generalizability of the results, effects reaching the level of significance in such a small population promotes practical relevance of the found effects. In clinical settings, vibration-enhanced stretching may serve as a targeted intervention to facilitate active movement pattern. For home-based use, the practical feasibility can be questioned as inducing additional vibration requires additional devices, a tradeoff between effectivity and practicability. While some underlying mechanisms were controlled, the results call for more precise evaluation techniques to reach higher internal result validity.