Cumulative Impact Loading and Cartilage Synthesis Biomarkers May Be Associated With Injury Risk in Female Collegiate Basketball Players

Abstract

Purpose: To evaluate whether cumulative impact load and serum biomarkers are related to lower-extremity injury and to determine any impact load and cartilage biomarker relationships in collegiate female basketball athletes.

Methods: This was a prospective longitudinal study evaluating lower-extremity impact load, serum cartilage biomarkers, and injury incidence over the course of a single collegiate women's basketball season. Data were collected from August 2022 to April 2023; no other follow-up after the cessation of the season was conducted in this cohort. Inclusion criteria for the study included collegiate women's basketball athletes, ages 18 to 25 years, who were noninjured at the start of the study time frame (August 2024). Cartilage synthesis (procollagen II carboxy propeptide and aggrecan chondroitin sulfate 846 epitope) and degradation (collagen type II cleavage) biomarkers were evaluated at 6 season timepoints. Impact load metrics (cumulative bone stimulus, impact intensity) were collected during practices using inertial measurement units secured to the distal medial tibiae. Injury was defined as restriction of participation for 1 or more days beyond day of initial injury. Cumulative impact load metrics were calculated over the week before any documented injury and blood draws for analysis. Point biserial and Pearson product moment correlations were used to determine the relationship between impact load metrics, serum biomarkers, and injury.

Results: Eleven collegiate women's basketball athletes (height: 1.86 meters, mass: 82.0 kg, age: 20.54 years) participated. Greater medium-range (6-20 g) cumulative impact intensities during week 5 and 6 for both limbs (r = 0.674, P = .023) and high-range (20-200 g) during week 8 for both limbs (0.672, P = .024) were associated with injury. Greater cumulative bone stimulus was associated with increased procollagen II carboxy propeptide levels before conference playoffs for right (r = 0.694, P = .026) and left (r = 0.747, P = .013) limbs. Greater chondroitin sulfate 846 epitope levels at off-season-1 (r = 0.729, P = .017), and at the beginning of the competitive season (r = 0.645, P = .044) were associated with season-long injury incidence.

Conclusions: In this study, we found that moderate-to-high intensity impacts (6-200 g) early in the season were associated with subsequent injury among female collegiate basketball players. Increased cartilage synthesis at various time points was correlated with increased cumulative bone stimulus metrics and season-long injury incidence in this population.

Level of evidence: Level IV, prognostic case series.

Fig 1

This is a figure of the prospective, longitudinal study in a collegiate women’s basketball team over the course of the 2022-2023 season. The timeline depicts the frequency and timing of the serum blood draw collections, the daily collection of impact load metrics using the inertial measurement units, and the daily collection of injury status, recorded by the team athletic trainer.

Fig 2

Shown are the variations in impact load, a unitless metric that is a surrogate of the impact load that is experienced by the tibia during court-based activities, for left (L), right (R) and both limbs (L+R) over the course of a 25-week collegiate women’s basketball season. This figure also denotes with asterisks when a lower-extremity joint injury occurred during the season.

Fig 3

Shown are a series of scatterplots (a-g) that visualize the statistically significant point biserial correlations for the right, left, and both limbs (total) that were observed during week 5 (preseason), week 6 (preseason), and week 8 (regular season) between the number of medium and high impacts taken over the course of those weeks and subsequent lower-extremity injury occurrence. The R² value is also listed in the upper right-hand corner of the scatter plots.

Fig 4

Scatterplot is shown that represents the correlation between greater levels of aggrecan chondroitin sulfate 846 epitope (CS846) and lower levels of cumulative bone stimulus of the right limb at the regular season 1 (start of the regular season) timepoint. An R² value is also listed in the upper right-hand corner of the scatter plots.

Fig 5

Scatterplot is shown that depicts the relationship between increased procollagen II carboxy propeptide (CPII) levels and increased cumulative bone stimulus of both the left and right limbs before conference playoffs time point.

Fig 6

Shown are the minimum, maximum and median cartilage biomarker levels (a-c) and mean cumulative bone stimulus of the left (L) and right (R) limb over the duration of a 25-week collegiate women’s basketball season. Cumulative bone stimulus is a unitless metric calculated by taking the peak resultant acceleration (impact) from every foot contact with the ground throughout the duration of the session (practice). Fluctuations in the serum biomarker concentrations of procollagen II carboxy propeptide (CPII), aggrecan chondroitin sulfate 846 epitope (CS846), and collagen type II cleavage (C2C) concentrations, presented as nanograms per milliliter, are represented at each of the 6 study time points (off-season 1, preseason, regular season 1, regular season 2 [midpoint of regular season], before conference playoffs, off-season 2 [after cessation of National Collegiate Athletic Association play]).

Fig 7

Shown are 2 scatterplots (a-b) that depict the small relationship between greater levels of aggrecan chondroitin sulfate 846 epitope (CS846) and the season-long injury incidence (i.e., greater number of injuries sustained over the season) at both the off-season 1 and beginning of the regular season time points.