Validation of an inertial measurement unit to determine countermovement jump height

Abstract

Background Vertical jump highs are used to quantify performance in the lower extremities. The aim of this study was to validate a wearable inertial measurement unit (IMU) for purpose of estimating countermovement jump height using the following methods: numerical double integration (NDI), takeoff velocity (TOV) and flight-time (FT). Methods Fifteen students each performed three jumps in two different sessions, four weeks apart. Jump-heights calculated from motion capture and force plate were used as gold standard for global IMU position and center of mass (CoM) displacement, respectively. Results The NDI method showed higher estimates for global position (1.39 cm, p = 0.025), and for CoM displacement (4.20 cm, p < 0.001). Narrow limits of agreements (LoA) were found (<4.8 cm). Further, a low tolerance level of determining equivalence (delta) between the two sessions regarding both global and CoM displacement (±2.80 and ± 2.90 cm) suggesting reasonable test-retest reliability. Similar bias was found for TOV and FT (p < 0.015) and wide LoAs were found for global position and for CoM displacement (TOV: ±7.05 and ± 9.36 cm, AT: ±9.27 and ± 8.49 cm). Further, high delta between the two sessions (TOV: ±3.50 cm, FT ±4.00 cm) showed poor test-retest reliability. Conclusion Estimation of countermovement jump height using an IMU leads to the most accurate measurements applying the NDI-method. Countermovement jump estimated with an IMU can reliably evaluate functional performance in the lower extremities in young or in sports active patients after surgery or after rehabilitation. Countermovement jump with an IMU allows performing the test without a force plate and thus serves as an objective outcome measure in clinical practice.

Acquisition of Lower-Limb Motion Characteristics with a Single Inertial Measurement Unit—Validation for Use in Physiotherapy

“…The video-MA derived the jump height directly from the vertical z-position of several markers on the lower leg and thigh—maximum position z minus position z 0 when standing upright before the jump. The different methods to determine the jump height were described and compared by [ 23 ]. In addition, height was calculated from flight time, but the IMU sensor attached to the back of the foot [ 24 ] also found accurate results.…”

Accuracy of Inertial Measurement Units When Applied to the Countermovement Jump of Track and Field Athletes

“…A force plate (FP) is often used to measure CMJ ability, due to its high accuracy and validity, allowing parameters such as force, impulse, power, acceleration, velocity, and displacement to be determined [ 5 ]. However, FPs require extensive data processing, are expensive, and are difficult to transport [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Other validated and applied devices are more suitable, affordable, and accessible, such as jump reach systems (Vertec) [ 15 ], contact belt systems [ 8 ], the mobile phone MyJump application [ 16 ], and optical time systems (Optojump; Microgate, Bolzano, Italy) [ 10 ].…”

“…Inertial Measurement Units (IMUs) have recently been applied in VJ testing, due to their applicability on any surface, ease of transportation provided by their small size, and ability to provide temporal and kinematic parameters, which may have a direct relation to kinetic parameters [ 13 , 14 , 17 , 18 , 19 , 20 ]. IMUs are micro-electromechanical sensor systems (MEMSs) that incorporate an accelerometer, a gyroscope, and a magnetometer [ 19 ].…”

“…IMUs are micro-electromechanical sensor systems (MEMSs) that incorporate an accelerometer, a gyroscope, and a magnetometer [ 19 ]. Studies have suggested many kinds of IMUs as valid devices for obtaining the jump height [ 11 , 12 , 13 , 14 , 17 ] and accuracy in order to determine the flight time and the center of mass (CoM) displacement in CMJs and CMJs with arms when applied to specific algorithms [ 18 ]. Furthermore, different IMU positions have been tested [ 21 ] in the CMJ.…”

“…Furthermore, different IMU positions have been tested [ 21 ] in the CMJ. Rantalainen et al [ 22 ] suggested a position on the back midline at the L3 to L5 level, and most studies placed the IMU on the trunk at the level of the fifth lumbar vertebra (L5) [ 11 , 12 , 13 , 14 , 18 , 19 ]; it was also placed on the calcaneus [ 19 ].…”