Background:
Core stability has been suggested to influence lower extremity functioning and might contribute to the development of lower extremity overuse injuries. However, prospective studies to ...investigate this relationship are limited.
Purpose:
To research the role of different components of core stability as risk factors for the development of lower extremity overuse injuries.
Study Design:
Cohort study; Level of evidence, 2.
Methods:
A total of 142 first-year physical education students participated in this study. They were tested in 2015 and were prospectively followed for 1.5 years by means of a multilevel injury registration method. Three participants were excluded owing to physical complaints during testing. As such, 139 participants were included in the statistical analysis. At baseline, dynamic postural control, isometric core and hip muscle strength, core muscle endurance, core neuromuscular control and proprioception, and functional movement were measured for all participants. Competing risk regression analyses were performed to identify significant contributors to the development of lower extremity overuse injuries.
Results:
During the follow-up period, 34 (24%) of the 139 participants developed a lower extremity overuse injury. Significant predictive effects for an overuse injury were found for an increased side-by-side difference in dynamic postural control (P = .038), decreased isometric hip extension:flexion strength ratio (P = .046), and decreased abdominal core muscle endurance (P = .032).
Conclusion:
This study identified measures for dynamic postural control, core muscle strength, and core muscle endurance as significant risk factors for the development of overuse injuries after statistical model building. However, core neuromuscular control and proprioception and functional movement might not allow clinicians to identify patients at risk. These accessible, reliable screening tools could be used in clinical practice with regard to screening and injury prevention for overuse injuries. Injury prediction based on this model needs to be done with caution given the low relative predictive accuracy (53%).
Patellar tendinopathy (PT) is a highly prevalent overuse injury in volleyball and is often linked with overloading of the patellar tendon. Little is known, however, about whether and how patellar ...tendon loading is affected by fatigue during the most challenging jump activity in volleyball. Therefore, this study investigates the effect of a high-intensity, intermittent fatigue protocol on movement alterations in terms of patellar tendon loading during a volleyball spike jump.
Forty-three male volleyball players participated in this study. Three-dimensional full-body kinematics and kinetics were collected when performing a spike jump before and after the fatigue protocol. Sagittal plane joint angles, joint work and patellar tendon loading were calculated and analyzed with curve analyses using paired sample t-tests to investigate fatigue effects (p < 0.05).
Fatigue induced a stiffer lower extremity landing strategy together with prolonged pelvis-trunk flexion compared to baseline (p = 0.001-0.005). Decreased patellar tendon forces (p = 0.001-0.010) and less eccentric knee joint work (-5%, p < 0.001) were observed after the fatigue protocol compared to baseline.
Protective strategies seem to be utilized in a fatigued state to avoid additional tensile forces acting on the patellar tendon, including proximal compensations and stiff lower extremity landings. We hypothesize that players might be more prone for developing PT if eccentric patellar tendon loads are high in the non-fatigued state and/or these loads are somehow not decreased after fatigue.
Short-term fatigue protocols simulating sports participation are scarce and not well-documented in jump-landing sports. Therefore, this study investigated physiological and physical responses ...following high-intensity, intermittent exercise protocols (HIIPs) with a standardized level of subjective exhaustion (Borg ≥18/20) and a modified fixed version of five circuits (HIIP-5) for future inclusion in biomechanical screening protocols. Twenty male volleyball and basketball players participated in this study to complete the HIIP and the HIIP-5. Physiological and physical variables were assessed before and up to 30 min after cessation of both protocols. Regarding physiological variables, heart rate values increased (+104 bpm, p < 0.001) and remained elevated up to 30 min (+34 bpm, p < 0.001), and blood lactate levels increased (+17 mmol/l, p < 0.001) compared to baseline. Regarding physical variables, decreased jump height (−4 cm, p = 0.001–0.009) and quadriceps muscle strength (p = 0.001−0.050) were observed up to 30 min compared to baseline. The type of the fatigue protocol did not have an effect on the investigated variables (p > 0.05). To conclude, both the HIIP and the HIIP-5 seem valuable tools to induce acute and long-lasting responses, providing a sufficiently large time window of 30 min within which biomechanical markers of injury can be assessed under fatigued conditions in future risk factor screenings. In practice, the fatigue protocol can be terminated after only five circuits if athletes had not yet been stopped at that point due to exhaustion (Borg ≥18/20).
Fatigue has often been considered a risk factor for developing sports injuries, modulating lower extremity jump-landing biomechanics. The impact of fatigue on proximal trunk and pelvic biomechanics ...has been suggested to play an important role in lower extremity loading and injury risk, yet the available evidence remains ambiguous as the trunk and pelvis were often not the primary focus of research. Therefore, the purpose of this systematic review was to determine how fatigue affects trunk and pelvic three-dimensional jump-landing biomechanics. PubMed (MEDLINE), Web of Science, Embase, CINAHL and SPORTDiscus were consulted up to and including April 2022 for potential studies investigating the effect of fatigue on trunk and pelvic kinematics, kinetics and/or muscular activity during jump-landing tasks in healthy, physically active populations. Methodological quality of the studies was assessed by the modified Downs and Black checklist. Twenty-one studies were included and methodological quality was moderate to high among these studies. The results indicate prevailing evidence for more trunk flexion during standardized jump-landing tasks after lower extremity muscle fatigue. Otherwise, lumbo-pelvic-hip muscle fatigue does not seem to elicit major detrimental changes to these jump-landing biomechanics. Although a wide variability of trunk and pelvic jump-landing strategies was observed, the results provide evidence for increased trunk flexion after lower extremity muscle fatigue. This proximal strategy is suggested to help unload fatigued lower extremity structures and lack of this compensation might increase knee injury risk.
Hamstring injury prevention puts emphasis on optimizing the muscle's strength-length relationship. To assure appropriate muscle length, flexibility training is imperative. As neurodynamics play an ...important role herein, the goal of this study was to explore the intervention effect of home-based neurodynamic slider program on hamstring flexibility. Fifty physically active male subjects were randomly assigned to either performing a neurodynamic sliding technique (3 × 20 reps) or a static stretching protocol (3 × 30″) on a daily basis for a 6-week period. Hamstring flexibility was assessed by means of the Straight Leg Raise at baseline, immediately after the intervention and after 4 weeks follow up. There was no between group baseline difference in hamstring flexibility. The repeated measure ANOVA showed a significant interaction effect for group × time (
< 0.001). Independent sample
-test showed a significantly higher increase in flexibility gain in the neurodynamic group immediately after the intervention (
< 0.001), as well as at 4 weeks retention analysis (
= 0.001) compared to the static stretch group. In conclusion, neurodynamic sliders might be more efficient than regular static stretching in affecting hamstring flexibility in the long run.
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