Biomechanical analysis of the circular friction hand massage

Abstract

Abstract. BACKGROUND: A massage can be beneficial to relieve muscle tension on the neck and shoulder area. Various massage systems have been developed, but their motions are not uniform throughout different body parts nor specifically targeted to the neck and shoulder areas. OBJECTIVE: Pressure pattern and finger movement trajectories of the circular friction hand massage on trapezius, levator scapulae, and deltoid muscles were determined to develop a massage system that can mimic the motion and the pressure of the circular friction massage. METHODS: During the massage, finger movement trajectories were measured using a 3D motion capture system, and finger pressures were simultaneously obtained using a grip pressure sensor. RESULTS: Results showed that each muscle had different finger movement trajectory and pressure pattern. The trapezius muscle experienced a higher pressure, longer massage time (duration of pressurization), and larger pressure-time integral than the other muscles. CONCLUSIONS: These results could be useful to design a better massage system simulating human finger movements.

Ultra-Sensitive Strain Sensor Based on Flexible Poly(vinylidene fluoride) Piezoelectric Film

“…The potential difference and pressure exhibit a linear relationship with a slope of 0.028 mV/kPa and an intercept of 5 × 10 −4 mV, implying very-low-level interference. A pressure under 178 kPa would generate signal interference less than 5 mV which is negligible [ 16 , 17 ]. In addition, the dependence of interference on array electrode size has been investigated.…”

“…Real-world applications, such as patched biosensor for detecting the human body pressure, demand multipoint sensing, structurally flexibility, and ultra-high sensitivity [ 14 – 16 ]. In this reported work, a 4 × 4 flexible sensor array based on piezoelectric PVDF film is demonstrated, showing ultra-high sensitivity of 12 mV/kPa and fast output response of 2.5 μs.…”