Background: Some swimmers reach high performance level at a relatively young age. The purpose of this study is to determine the relationship between adolescent female swimmers’ 100 m front crawl race ($V_{total100}$) and several anthropometry, body composition, and physiological and specific strength indices. Methods: Nineteen adolescent female swimmers were examined for biological age (BA) and body composition. Oxygen uptake was measured during water-flume stage-test front crawl swimming with ventilatory thresholds examination. Specific strength indices were assessed during 30 s of tethered swimming. Stroke rate (SR), stroke length (SL), and stroke index (SI) were also examined. Results: BA was strongly correlated with anthropometrics and tethered swimming strength indices, and showed moderate to strong correlation with ventilatory thresholds. Speed of swimming in the race was moderately to largely correlated with speed at $\dot{V}{O}_{2 }max$−$V_{\dot{V}{O}_{2}max}$ (r = 0.47–0.55; p < 0.05)—ventilatory thresholds ($V_{AT}$,$V_{RCP}$) (r = 0.50–0.85; p < 0.05), SL (r = 0.58–0.62; p < 0.05), and SI (r = 0.79–0.81; p < 0.01). Conclusion: Results confirmed a significant role of biological maturation mediation on body composition and body size, ventilatory indices, and specific strength indices. BA was not a significant mediation factor influencing the swimming kinematics (SL, SI) and speeds of $V_{AT}$, $V_{RCP}$ or $V_{\dot{V}{O}_{2 }max}$, which were strong predictors of the 100 m race.

To investigate isometric and isokinetic hip strength as well as dynamic balance in males with chronic ankle instability (CAI) and explore potential associations between hip strength, dynamic balance, and self-reported instability. Cross-sectional study. University laboratory. Fifty male participants (25 with CAI and 25 healthy controls). Hip isometric and isokinetic torque normalized to body weight, Lower Quarter Y-balance Test (YBT-LQ), the Polish version of The Cumberland Ankle Instability Tool (CAIT-PL). Significant differences were observed only in the hip isometric abductors/adductors strength ratio (p = 0.034, ES = 0.65), which was lower in the CAI group. CAI participants showed reduced dynamic balance in posterolateral reach (p = 0.006, ES = 0.92) and composite score of YBT-LQ (p = 0.012, ES = 0.91). There was a moderate positive correlation between dynamic balance and hip abductors strength during posteromedial (r = 0.40, p = 0.049) and posterolateral (r = 0.40, p = 0.048) YBT-LQ reaches, and isometric hip abductors strength moderately positively correlated with self-reported instability (r = 0.46, p = 0.021) in the CAI group. Males with CAI exhibit deficits in frontal plane hip isometric strength, specifically in the hip abductor/adductor ratio, while no deficits were observed in isokinetic strength. The relationships between hip abductors strength, dynamic balance, and self-reported ankle instability may suggest the importance of hip abductors isometric strength for functional outcomes in CAI-patients.

The purpose of this study was to examine the relationship between a unique complex of predictors and 100 m front crawl race kinematics and swimming speed. In 28 male competitive swimmers (age: 19.6 ± 2.59 years), the following groups of predictors were assessed: (a) the morphologic, (b) the functional upper limb range of motion, and (c) the anaerobic indices of arm-cranking and a series of countermovement jumps. The Pearson product-moment correlation coefficient was calculated to distinguish the predictors and the swimming results. The main finding was that the indices of the power (arm-cranking) and the work (countermovement jump) generated in the anaerobic tests showed a significant and higher correlation with stroke length and stroke index than total body length, upper limb range of motion, or hand and forearm surface area. These results were obtained in accordance with the high swimming economy index relation to clear surface swimming speed. This study reveals that the strength generated by the limbs may represent a predictor of swimming kinematics in a 100 m front crawl performance.

Background/Objectives: This paper analyzes the movement and relationships within the lumbopelvic–hip complex during forward trunk bending in young women with chronic low back pain. Methods: This study involved 24 women aged 20–24 with chronic low back pain. They were randomly divided into two equal-sized groups: Group 1 participated in a 12-week functional training program, and Group 2 was a control without any intervention. The level of perceived pain was assessed using the Visual Analog Scale (VAS). Qualitative motion analysis was performed using the BTS SMART-D system. Custom indicators were developed to evaluate the angular relationships and ranges of motion in the lumbar spine and the lumbopelvic–hip complex. The functional training program consisted of three sections: motor control and stabilization, muscle strengthening, and stretching exercises. Statistical analysis was performed using Statistica 13.3. Results: The therapy resulted in a reduction in perceived pain levels reported by the participants. There was a significant improvement in the quality of the forward trunk bending pattern in women who underwent functional training. Conclusions: Significant modifications in the quality, technique, and angular relationships within the lumbopelvic–hip complex were observed during the forward trunk bending pattern in women undergoing functional training. It has proven to be an effective form of therapy for chronic low back pain.

Background/Objectives: Although considerable progress has been made in understanding lateral ankle sprains (LAS) and chronic ankle instability (CAI), recurrent injury rates remain high. This highlights the need to explore additional contributors such as comprehensive lower-limb gait analysis, including multisegmented foot models and proximal joint kinematics and strength. This study aimed to assess multisegmented foot and lower-limb kinematics throughout the gait cycle in individuals with CAI compared to healthy controls. Additionally, associations between hip abductor strength and frontal plane ankle kinematics were examined. Methods: Fifty males (25 with CAI and 25 healthy controls) participated in this cross-sectional study. Gait analysis was conducted using a BTS SMART 3D motion capture system to assess multisegmented foot and proximal joint kinematics. Isometric hip strength was measured using a Biodex dynamometer. Statistical Parametric Mapping (SPM) was used to assess group differences, and correlations were calculated between hip abductor strength and ankle kinematics. Results: The CAI group demonstrated significantly greater calcaneus abduction relative to the shank in the transverse plane between 88% and 93% of the gait cycle (MD = −3.50°, 95% CI [−5.60, −1.40], d = −0.95, p = 0.037). No other statistically significant between-group differences in hip, knee, or foot segment kinematics were detected. Furthermore, correlations between hip abductor strength and ankle frontal plane kinematics were not significant. Conclusions: Males with CAI demonstrated altered rearfoot kinematics in the transverse plane during the terminal swing phase. The multisegmented foot model was valuable in detecting subtle deviations and emphasized the importance of including the swing phase. Hip abductor strength was not associated with ankle kinematics, suggesting that its potential role in CAI may involve other mechanisms. These findings may support clinical gait assessment and rehabilitation planning by highlighting the importance of evaluating all foot segments and the entire lower limb, rather than focusing solely on the ankle joint. Segment-specific deviations, particularly those emerging during the swing phase, may help guide targeted interventions aimed at improving foot positioning in males with CAI.

Background: The main aim of this study was to identify the differences between subgroups of swimmers based on physiological (peak oxygen uptake—VO₂peak), strength (average tethered swimming force—60F_ave), stroke kinematics (v₁₀₀—swimming speed at 100 m front crawl, stroke rate—SR, stroke length—SL), and anthropometrical (i.e.,: biological age—BA, body height—BH, body mass—BM) factors within swimmers at different levels of maturity (BA). Methods: This study involved 39 female swimmers (age: 12.88 ± 0.54 years, BA: 13.98 ± 1.91 years). Cluster analysis (k-cluster) and stepwise multiple regression was performed. Results: Significant correlations were observed between v₁₀₀ and BA, 60F_ave, AS, VO₂peak. Stepwise multiple regression indicated 60F_ave and VO₂peak as the main explanatory variables of v₁₀₀ (R² = 0.60, p < 0.0001). Cluster analysis allowed us to distinguish three groups of swimmers, differing in BA (cluster 1: 14.07 ± 0.96 years, cluster 2: 17.05 ± 1.53, cluster 3: 11.94 ± 0.95) and v₁₀₀, as well as in BH, FFM, AS. Conclusions: There were differences between cluster groups, with early mature swimmers characterized by the highest BH, FFM, AS, 60F_ave, and VO₂peak. Probably, biologically younger late mature swimmers (cluster 3) are slower than the other 2 groups (cluster 1 and 2) because of being less somatically developed. Based on these study results, coaches should ensure further development of aerobic and anaerobic conditioning among normal mature swimmers with simultaneous focus on improving technique skills among early mature ones.