Tracking the Reliability of Force Plate-Derived Countermovement Jump Metrics Over Time in Female Basketball Athletes: A Comparison of Principal Component Analysis vs. Conventional Methods

Longitudinal Monitoring of Biomechanical and Psychological State in Collegiate Female Basketball Athletes Using Principal Component Analysis

“…This method of biomechanical assessment during vertical jump testing has been deemed valid when compared to the in-laboratory gold standard [ 65 , 66 ]. Moreover, the reliability and ecological validity of these CMJ metrics were assessed in work paralleled to this investigation by our laboratory and were found to be highly reliable (ICC ≥ 0.90) when assessed longitudinally, while the asymmetry metrics were relatively independent of one another which highlighted the need to concurrently collect traditional and sport-specific asymmetry measures [ 38 , 63 ]. Finally, weekly questionnaires were completed via Google Forms on the athletes own volition on Monday mornings using a questionnaire built by a multidisciplinary team of researchers in collaboration with the McMaster University Strength and Conditioning team.…”

“…The correlation between the array of metrics, both on- and off-court, gave credence to the use of a PCA as it suggested that these metrics may have some redundancy and share commonalities to similar, underlying components of biomechanical movement patterns (Supplementary Table 1 ). Additionally, the reliability of the biomechanical PCs and introspective and psychological state metrics were assessed across five consecutive and unperturbed (i.e., no scheduled periods of intensified competition or extended rest that would implicate the consistency of these measures) weeks in the 2022-2023 preseason using the same statistical approach previously outlined in a similar work by our laboratory [ 63 ]. The results of the current reliability analysis can be found in Supplementary Table 2 .…”

“…Interlimb asymmetry metrics were chosen due to the previously identified implications to sport performance and risk of injury [ 16 , 17 ], while impact load, step count, and average intensity were included given that the most frequent mechanism of injury in basketball relates to improper landings from vertical jumping or during change-of-direction-related tasks [ 1 , 64 ], and these metrics may provide a surrogate measure for the volume of such on-court activities. Second, four between-limb CMJ asymmetry measures (peak braking-, propulsive-, and landing-force, and average braking rate of force development asymmetry [ 63 ]), peak power production during the braking and propulsive phases of movement, countermovement depth (CMD), time to takeoff, jump height (JH), and the modified reactive strength index (RSI mod = JH/time to takeoff) were assessed weekly with the CMJ without an arm-swing using a portable bilateral force plate system (Hawkin Dynamics) with a sampling frequency of 1000 Hz. This method of biomechanical assessment during vertical jump testing has been deemed valid when compared to the in-laboratory gold standard [ 65 , 66 ].…”

“…The CMJ testing and on-court session procedures have been previously outlined and can be found in other works conducted by Keogh and colleagues [ 38 , 63 ]. Briefly, CMJ testing was conducted on Monday mornings after the completion of a low-to-moderate-intensity dynamic warm-up to prepare the neuromuscular system.…”

“…Briefly, CMJ testing was conducted on Monday mornings after the completion of a low-to-moderate-intensity dynamic warm-up to prepare the neuromuscular system. Participants performed three CMJ attempts without an arm-swing, self-selected their CMD, were cued to jump as high and quickly as possible, and were provided a minimum of 30-seconds of rest between successive attempts [ 63 ]. On-court sessions were completed between two and three times per week in which IMUs were positioned bilaterally anterosuperior to the medial malleoli throughout 90- to 120-minute basketball practices [ 38 ].…”