One possible modality to profile gait speed and stride length includes using wearable technologies. Wearable technology using global positioning system (GPS) receivers may not be a feasible means to measure gait speed. An alternative may include a local positioning system (LPS). Considering that LPS wearables are not good at determining gait events such as heel strikes, applying sensor fusion with an inertial measurement unit (IMU) may be beneficial. Speed and stride length determined from an ultrawide bandwidth LPS equipped with an IMU were compared to video motion capture (i.e., the “gold standard”) as the criterion standard. Ninety participants performed trials at three self-selected walk, run and sprint speeds. After processing location, speed and acceleration data from the measurement systems, speed between the last five meters and stride length in the last stride of the trial were analyzed. Small biases and strong positive intraclass correlations (0.9–1.0) between the LPS and “the gold standard” were found. The significance of the study is that the LPS can be a valid method to determine speed and stride length. Variability of speed and stride length can be reduced when exploring data processing methods that can better extract speed and stride length measurements.
Kinematic and kinetic changes in the lower extremities occur as an athlete becomes fatigued during vertical jumping; however, the specifics of these changes are not well-understood. Therefore, the purpose of this study was to quantify the influence of a sport-specific, vertical jumping fatigue protocol on the biomechanics of the ankle, knee, and hip joint. Twenty male varsity athletes performed repetitive standing countermovement squat jumps every 20 s until fatigued (vertical jump and reach height decreased to 88% of their maximum height for three consecutive jumps). The kinematics and kinetics of their lower extremities (ankle, knee, and hip) were quantified, and the ankle, knee, and hip joint’s moments, angular velocity, and joint power were compared. The participants performed an average of 175 jumps before they were classified as being fatigued. When they became fatigued, the peak power of the ankle and hip joints were substantially reduced due to a decrease in the angular velocity at both joints. Ankle and hip joint moments were unchanged. Peak power at the knee joint was also unchanged over the course of the jumping protocol. To maintain vertical jumping performance over the course of a game or to delay the influence of fatigue, training should be targeted at maintaining the angular velocity of the ankle and hip joints.
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