Injury incidence among adolescent and senior basketball players: a prospective study in 19 teams across an entire season.

OBJECTIVE: To quantify and compare injury incidence between national-level, adolescent and regional-level, senior, male basketball players competing in Serbia overall and according to injury mechanism (contact, non-contact, or overuse), exposure setting (training or games), and history (new or recurrent). METHODS: A total of 218 male basketball players from 19 teams (106 senior and 112 adolescent players) volunteered to participate in the study. Descriptive data regarding game and training injury incidence were gathered across all players and reported per 10,000 athlete-exposures (AE) with 95% confidence intervals. RESULTS: Overall, 26 injuries were reported across 52,509 AE. Ankle (n = 10, incidence rate [IR] = 1.90 [0.97, 3.40]) and knee injuries (n = 8, IR = 1.52 [0.71, 2.89]) accounted for 69% of all reported injuries, with only 1-2 injuries documented for other body regions. Ankle injuries were attributed to contact (60%, IR = 1.14 [0.46, 2.38]) or non-contact mechanisms (40%, IR = 0.76 [0.24, 1.84]). Most knee injuries occurred due to overuse (50%, IR = 0.76 [0.24, 1.84]) or non-contact mechanisms (38%, IR = 0.57 [0.15, 1.56]). Comparisons according to exposure setting revealed significantly higher knee (incidence rate ratio [IRR] = 9.95 [1.85, 53.41], p = 0.004) and ankle (IRR = 39.79 [7.94, 384.67], p < 0.001) injuries per 10,000 AE during games compared to training. Recurrent injuries were most prominent in the ankle (30% of all ankle injuries, p = 0.11). Total contact (p = 0.04), non-contact (p = 0.04), and recurrent IR (p = 0.005) were significantly higher in senior than adolescent players. CONCLUSION: The players examined were most susceptible to ankle and knee injuries, particularly during games compared to training. Ankle injuries were mostly attributed to player contact, while knee injuries were mostly attributed to overuse and non-contact mechanisms. Senior players were at a greater risk of sustaining contact, non-contact and recurrent injuries than adolescent players.

Effects of Different Loading Types on the Validity and Magnitude of Force-Velocity Relationship Parameters.

BACKGROUND: Force-velocity (F-V) relationship models gained popularity as a tool for muscle mechanical assessment. However, it is not clear whether the validity of the F-V relationship parameters (maximal theoretical force [F0], velocity [V0] and power [Pmax]) is affected using different load types: gravitational (W, rubber bands pulling the barbell downward), inertial (I, rubber bands pulling the barbell, which is equalized to the weight of the added plates upward), and combined (W + I, weight of the plates). HYPOTHESIS: Load type would affect both the magnitude and validity of F-V relationship parameters. The highest magnitude and validity was expected for F0 using a W, for V0 using an I, and for Pmax using a W + I load. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 13 resistance-trained men (body mass, 87.7 ± 11.2 kg and body height, 183.9 ± 6.4 cm) performed bench press (BP) throws (BPTs) using 3 types of loads against 30 to 80 kg. The validity of F-V relationship parameters was explored with respect to the tests used traditionally for force (maximal voluntary contraction and 1-repetition maximum [1RM]), velocity (maximal velocity achieved during almost unloaded tasks), and power (BPT against the 50%1RM and medicine ball throws) assessment. RESULTS: The W + I loading promoted the highest values of F0 and Pmax, while the highest magnitude of V0 was promoted by the I loading. The validity was acceptable for F0 obtained using the 3 loading conditions with respect to the BP 1RM (r range, 0.30-0.83), and V0 obtained using the I loading with respect to the stick throw (r = 0.54). CONCLUSION: The magnitude of the F-V relationship parameters is affected by load type, but their validity with respect to standardized tests is comparable, with the exception of the higher validity of V0 when obtained using the I loading. CLINICAL RELEVANCE: Any load type can be used for assessing F0, while I load should be selected when assessing V0.

Assessments of Ground Reaction Force and Range of Motion in Terms of Fatigue during the Body Weight Squat.

The purpose of this study was to analyse in detail body weight squat (BWS)' fatigue effect on the range of motions (ROM) of the hip, knee, ankle and ground reaction forces (GRF). Twenty male recreational athletes (24.0 ± 3.1 years, 178.85 ± 7.12 cm and 78.7 ± 11.45 kg) participated in this study. BWS were performed on four load cell platforms until the participants failed to continue. Participants performed 73 ± 27 repetitions and the duration to complete of the repetitions was 140.72 ± 62.28 s during the BWS exercise. The forefoot and hindfoot of the feet were on two load cells, thus, there were two under each foot. All of the data collected was divided into three sections for analysis (24 ± 9 repetitions for each). In terms of GRF of the fore feet and hind feet, significant differences and medium to large effect size were found between each section (p = 0.006~0.040, ES = 0.693~0.492). No significant differences were found between right and left leg in all sections. Significant differences were found in the ROM of the hip between the sections of first-third (p = 0.044, ES = 0.482) and second-third (p = 0.034, ES = 0.510), the ROM of the knee first-third (p = 0.014, ES = 0.602) and second-third (p = 0.005, ES = 0.701) and for the ROM of the ankle first-second (p = 0.045, ES = 0.479). As a result, end-of-exercise fatigue caused an increase in the ROM of the hip, knee and ankle. Thus, it is observed that fatigue induced increased ROM, also increases the GRF towards the forefeet.

Effect of Different Types of Loads on the Force-Velocity Relationship Obtained During the Bench Press Throw Exercise.

ABSTRACT: Cosic, M, Knezevic, OM, Nedeljkovic, A, Djuric, S, Zivkovic, MZ, and Garcia-Ramos, A. Effect of different types of loads on the force-velocity relationship obtained during the bench press throw exercise. J Strength Cond Res 35(9): 2401-2406, 2021-This study aimed (a) to evaluate the degree of linearity of the force-velocity (F-V) relationship across different types of loads, (b) to compare the magnitude of the F-V relationship parameters (maximum values of force [F0], velocity [V0], and power [Pmax]) between the different types of loads, and (c) to explore the concurrent validity of F0 with traditional measures of maximal strength. The F-V relationships of 15 physically active men (age: 20.9 ± 2.0 years, bench press 1 repetition maximum relative to body mass: 1.20 ± 0.10 kg·kg-1) were determined during the bench press throw exercise using predominantly gravitational (W), inertial (I), and combined (W + I) loads. The bench press maximal isometric force (Fiso) and the 1RM were also assessed. The individual F-V relationships were highly linear regardless of the type of load considered (median r [range] = 0.98 [0.94, 1.00]). The W + I load provided the largest value of F0 (972 ± 45 N; 6.0 and 14.6% higher than W and I, respectively), the I load the largest value of V0 (2.99 ± 0.34 m·s-1; 40.4 and 20.1% higher than W and W + I, respectively), and the W load the lowest value of Pmax (501 ± 46 W; -22.7 and -17.1% lower than I and W + I, respectively). The F0 obtained from the W load presented the highest association with Fiso and 1RM values (r > 0.90). The W + I load and the I load should be recommended to work closer to the F0 and V0 capacities, respectively. However, the W load should be recommended to assess maximal strength capacity through the value of F0.

Is Test Standardization Important when Arm and Leg Muscle Mechanical Properties are Assessed through the Force-Velocity Relationship?

The force-velocity (F-V) relationship observed in multi-joint tasks proved to be strong and approximately linear. Recent studies showed that mechanical properties of muscles: force (F), velocity (V) and power (P) could be assessed through the F-V relationship although the testing methods have not been standardized. The aim of the present study was to evaluate and compare F-V relationships assessed from two tests performed on a modified Smith machine that standardizes kinematics of the movement pattern. Fifteen participants were tested on the maximum performance bench press throws and squat jumps performed against a variety of different loads. In addition, their strength properties were assessed through maximum isometric force (Fiso) and one repetition maximum (1 RM). The observed individual F-V relationships were exceptionally strong and approximately linear (r = 0.98 for bench press throws; r = 0.99 for squat jumps). F-V relationship parameter depicting maximum force (F0) revealed high correlations with both Fiso and 1 RM indicating high concurrent validity (p < 0.01). However, the generalizability of F-V relationship parameters depicting maximum force (F0), velocity (V0) and power (P0) of the tested muscle groups was inconsistent and on average low (i.e. F0; r = -0.24) to moderate (i.e. V0 and P0; r = 0.54 and r = 0.64, respectively; both p < 0.05). We concluded that the F-V relationship could be used for the assessment of arm and leg muscle mechanical properties when standard tests are applied, since the typical outcome is an exceptionally strong and linear F-V relationship, as well as high concurrent validity of its parameters. However, muscle mechanical properties could be only partially generalized across different tests and muscles.