Effects of Lower Extremity Muscle Fatigue on Knee Loading During a Forward Drop Jump to a Vertical Jump in Female Athletes

Impact of different landing heights on the contact force in the medial tibiofemoral compartment and the surrounding muscle force characteristics in drop jumps

This study explored the impact of landing height on the tibiofemoral joint's medial compartment force (MCF) during drop jumps to help athletes prevent knee injury. Experienced male participants (N = 16) performed drop jumps with landing heights from 0.15 m to 0.75 m. Kinematic/kinetic parameters were collected using a motion capture system and a three-dimensional force platform. The Med-Lat Knee model was used to calculate biomechanical indicators of the knee joint, and data were analyzed using one-way analysis of variance and one-dimensional statistical parametric mapping (SPM1d). Findings indicated that landing height significantly affected the anterior-posterior and vertical MCF, flexion-extension torque, internal-external rotation torque, and vertical ground reaction force (p<0.05)-all increasing with elevated landing height-and significantly impacted the generated force of the vastus medialis, vastus lateralis, and vastus intermedius (p<0.05). SPM1d analysis confirmed these results within specific time intervals. Thus, both the knee moment and the MCF exhibited similar coordinated changes during drop jumps, indicating that these may be adaptive movement strategy. The impact of varying drop jump heights on muscle groups around the knee joint varied suggests that different heights induce specific muscular responses and improve muscle coordination to prevent knee joint injuries.

The effects of two different fatigue protocols on movement quality during anticipated and unanticipated change of directions in female soccer players

OBJECTIVE

This study compared neuromuscular control under two fatigue protocols during anticipated and unanticipated change of direction (COD) maneuvers and evaluated their effects on the risk of non-contact ACL injuries.

METHOD

Forty-five female soccer players (mean age: 22.22 ± 2.24 years; mean height: 166.24 ± 3.33 cm; mean mass: 59.84 ± 5.03 kg) were divided into three groups: functional fatigue (Soccer specific fatigue ptotocol-SOFT90), non-functional fatigue (Bruce protocol), and control group. Before and after the implementation of neuromuscular control fatigue protocols were evaluated using the cutting motion assessment score tool (CMAS). Two-dimensional (2D) videos were recorded during anticipated and unanticipated COD trials for both dominant and non-dominant legs.

RESULTS

Significant time effects (p < 0.05) and group-time interactions (p < 0.05) were observed in both anticipated and unanticipated conditions for both dominant and non-dominant legs after the fatigue protocols. The functional fatigue group exhibited higher CMAS changes, indicating poorer movement quality following fatigue. Notably, the non-dominant leg displayed amplified deficits during unanticipated COD maneuvers following the functional fatigue protocol.

CONCLUSIONS

Fatigue significantly impairs neuromuscular control, particularly in unanticipated COD situations, which increases the risk of non-contact ACL injuries. To mitigate this risk, coaches, trainers, and medical professionals should prioritize targeted training and injury prevention strategies, focusing on the non-dominant leg during unanticipated COD maneuvers.

Multi-joint protective effects of lumbar brace on lumbar, hip, knee, and ankle in parachute landing with backpack load

There were high injury risks on lumbar and lower limb joints in parachuting landing, and the lumbar brace could protect lumbar. Besides, a backpack load was necessary in parachute landing and increased the injury risk. This study aimed to evaluate multi-joints protective effects of the lumbar brace on lumbar and lower limb joints in parachuting landing with the backpack load. Seven participants landed from a 120 cm height platform without and with a lumbar brace and without and with a 5-kg backpack load, respectively. Infrared makers were pasted on trunk, pelvis, and lower limb in order to build a multi-rigid-body model for calculating kinematic and kinetic parameters. The joint angular displacements of lumbar and ankle and the peak vertical ground reaction force were significantly decreased from 29.2 ± 9.2°, 45.2 ± 7.8°, and 14.7 ± 2.0 bodyweight to 21.6 ± 4.9° (p < 0.05), 39.0 ± 10.1° (p < 0.05) and 10.7 ± 1.3 bodyweight (p < 0.05) respectively by the lumbar brace with no backpack load, and the joint angular displacement of hip was significantly increased from 52.6 ± 7.2° to 68.3 ± 12.5° (p < 0.05). The joint angular displacement of lumbar and ankle were significantly decreased from 29.0 ± 5.0° and 53.8 ± 5.1° to 25.1 ± 5.2° (p < 0.05) and 48.5 ± 2.5° (p < 0.05) respectively by the lumbar brace with the backpack load, and the joint angular displacement of hip and knee were significantly increased from 60.1 ± 8.2° and 110.1 ± 9.3° to 69.7 ± 13.2° (p < 0.05) and 116.8 ± 5.8° (p < 0.05), respectively. The lumbar brace could provide the multi-joint protective effect by decreasing injuries of lumbar and ankle in landing both without and with the backpack load.

Landing Posture in Elite Female Athletes During a Drop Vertical Jump Before and After a High-Intensity Ergometer Fatigue Protocol: A Study of 20 Japanese Women's Soccer League Players

Background

Even elite athletes, who usually show stable postural control, sometimes cannot control their posture after high-load training. This instability may contribute to anterior cruciate ligament injury.

Purpose/Hypothesis

The purpose of this study was to evaluate the landing posture of elite female soccer players before and after a novel high-intensity fatigue-inducing exercise protocol. We hypothesized that the landing posture will change before versus after the fatigue protocol.

Study Design

Descriptive laboratory study.

Method

The study participants were 20 female elite soccer players. All athletes performed 3 drop vertical jumps (DVJs), pedaled an ergometer 8 times with full force for 10 seconds each (fatigue protocol), and then repeated the 3 DVJs. We measured and compared the athletes' blood lactate levels before and after the fatigue protocol, as well as the hip flexion, knee flexion, and ankle dorsiflexion angles and final landing posture during the DJVs.

Results

Blood lactate levels increased significantly pre- to postprotocol (from 2.7 ± 1.9 to 15.0 ± 3.6 mmol/L; P < .001), while there were decreases in hip flexion angle (from 35.0° ± 11.2° to 22.4° ± 8.8°; P < .001) and ankle dorsiflexion angle (from 26.4° ± 3.9° to 20.0° ± 3.7°; P < .001). The number of athletes who could not maintain a stable DVJ final landing posture increased from 10% before the fatigue protocol to 70% after.

Conclusion

The elite female athletes in our study showed significant decreases in hip flexion and ankle dorsiflexion angles in the DVJ landing after a fatigue-inducing protocol. Most elite athletes were unable to maintain a stable posture on the DVJ landing after the fatigue protocol.

Clinical Relevance

This study advances our understanding of how elite athletes land in a fatigued state.

The Effect of Fatigue on Trunk and Pelvic Jump-Landing Biomechanics in View of Lower Extremity Loading: A Systematic Review

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.

Effects of Body Posture and Different Exercise Intensity on Athletes’ Limb Injury

The purpose of this study was to solve the problem of the influence of body posture and different exercise intensity on athletes' limb injuries, to meet the needs of understanding athletes' injuries, and to make up for the lack of investigations on athletes' limb injuries; this also increases the chances of an athlete avoiding injury. Severe acute sports injuries of high-level gymnasts endanger the personal safety of athletes. Many movements in gymnastics are done in the air much higher than the ground, and there is no fulcrum when the athlete does the movements; this just can only maintain balance and change your body posture through your own feelings, a slight error can easily cause your head or upper body to fall down, and the fragile spine cannot withstand the strong impact of the ground, resulting in high vertebral fractures, high paraplegia, and even death. Therefore, through a survey of 126 rhythmic gymnasts who participated in the 2011 “China Art Sports Cup” China Rhythmic Gymnastics Championship, a total of 172 injuries were found in 136 gymnasts, and the injury risk analysis was carried out from the main characteristics of the injuries.

Bilateral counter movement jump, squat, and drop jump performances in deaf and normal-hearing volleyball players: a comparative study

Since deaf athletes do not have any physical deficiencies, it is known that they can easily participate in sports competitions if their communication problems are resolved. This study aimed to compare the performances of olympic deaf and elite normal-hearing volleyball players in different jumping test protocols. A total of 26 male volleyball players participated in the study, comprised of 12 olympic level deaf and 14 elite level normal-hearing. Following anthropometric measurements, athletes performed bilateral counter movement, squat and drop jump tests on a force plate. Each test was performed 3 times with maximal effort separated by 45 seconds of passive recovery and the mean of the three trials was selected for analysis. Independent Samples t-test was used to compare the differences in mean values of jumping test parameters between the groups. Normal-hearing athletes are observed to have significantly better scores than deaf athletes in all test protocols. Considering that the number of studies on athletic performance in deaf athletes is limited, it can be said that our study will contribute to researchers and coaches in respect of detecting a key ability in volleyball, such as jumping, in different jump protocols.

Examining the Dynamic Nature of Anterior Cruciate Ligament Injury Risk Factors in Women's Collegiate Soccer

CONTEXT

Anterior cruciate ligament (ACL) injuries are a common and devastating injury in women's soccer. Several risk factors for ACL injury have been identified, but have not yet been examined as potentially dynamic risk factors, which may change throughout a collegiate soccer season.

DESIGN

Prospective cohort study.

METHODS

Nine common clinical screening assessments for ACL injury risk, consisting of range of motion, movement quality, and power, were assessed in 29 Division I collegiate women's soccer players. Preseason and midseason values were compared for significant differences. Change scores for each risk factor were also correlated with cumulative training loads during the first 10 weeks of a competitive soccer season.

RESULTS

Hip external rotation range of motion and power had statistically significant and meaningful differences at midseason compared with preseason, indicating they are dynamic risk factors. There were no significant associations between the observed risk factor changes and cumulative training load.

CONCLUSIONS

Hip external rotation range of motion and power are dynamic risk factors for ACL injury in women's collegiate soccer athletes. Serial screening of these risk factors may elucidate stronger associations with injury risk and improve prognostic accuracy of screening tools.

Effects of Maximal Effort Running on Special Agents' Loaded and Unloaded Drop Jump Performance and Mechanics

The purpose was to investigate the effect of load and fatigue on landing forces and mechanics. Thirteen Department of State special agents first completed drop jump testing, a maximal treadmill test, and another round of drop jump testing. During drop jump testing, agents performed 3 maximal effort drop jumps from 30 cm with body mass only (unloaded) or a 15 kg weight-vest (loaded). A force plate was used to collect force–time data, while two laptops were placed 3 m from the force plate from frontal and sagittal planes. Two-way analyses of variance were used to analyze the effect of load and fatigue on landing forces and Landing Error Scoring System (LESS) with alpha of p < 0.05. Dropping from 30 cm with 15 kg resulted in greater landing impulse, which was driven by increases in contact time. The loaded condition also resulted in lower jump height and reactive strength indexes. After the maximal graded treadmill test there were no further changes in drop jump ground reaction forces or performance. However, relative aerobic capacity was related to impulse changes following the treadmill test in unloaded (R² = 0.41; p = 0.018) and loaded conditions (R² = 0.32; p = 0.044). External loads of 15 kg increased impulse and contact time and resultantly decreased drop jump height and reactive strength indexes. It is encouraged that training protocols be aimed to concomitantly improve aerobic capacity and lower body power. Plyometric training with progressive overloading using external loads may be helpful, but further research is warranted.

The Effects of Whole-Body Vibration on Fatigue in Vertical Jump Performance and Isometric Mid-Thigh Pull Measures

The purpose of this study is to determine the effects of coupling WBV and acute muscular fatigue to determine its effects on countermovement vertical jump (CMVJ) performance and isometric mid-thigh pull (IMTP). Twenty-eight healthy active adults volunteered for five-day study. Testing sessions 2–5 included one of four conditions: No WBV and no fatigue (CON), WBV and fatigue (WBV + FAT), WBV and no fatigue (WBV), and no WBV and fatigue (FAT). WBV was performed using a frequency of 50 Hz and a low amplitude while performing quarter squats for a total of 4 min with a 30 s rest or work ratio. Lower-body fatigue induced using Bosco fatigue protocol. CMVJ and IMTP were performed on force plates. SPSS was used to perform a 2 × 2 Repeated Measures ANOVA. Significant main effects were found for fatigue in CMVJ-height and CMVJ-peak ground reaction force, no significant main effect for WBV, and no significant interactions. Lower-body fatigue decreases vertical jump performance, and WBV did not attenuate the detrimental effects of lower-body fatigue.

Muscle Damage and Performance after Single and Multiple Simulated Matches in University Elite Female Soccer Players

The present study aimed to compare changes in muscle damage and performance parameters after playing single versus multiple soccer matches to examine fixture congestion effects on performance. Twelve elite female university soccer players performed single, three and six consecutive 90-min bouts of the Loughborough Intermittent Shuttle Test (LIST) with ≥12-weeks between conditions in a pseudo-randomized order. Heart rate, blood lactate, rating of perceived exertion and covering distance in each LIST were examined. Changes in several types of muscle damage (e.g., maximal voluntary isometric torque of the knee extensors: MVC-KE) and performance measures (e.g., Yo-Yo Intermittent Recovery Test level 1: YYIR1) were taken before each LIST, 1 h, and 1–5 d after the last LIST. The total distance covered during the LIST was shorter (p < 0.05) in the 2nd–3rd, or 2nd–6th LISTs when compared with the 1st LIST. Changes (p < 0.05) in all measures were observed after the LIST, and the greatest changes were observed after the six than after the three LISTs followed by one LIST (e.g., largest changes in MVC-KE: −26 > −20 > −14%; YYIR1: −31 > −26 > −11%). Many of the variables did not recover to the baseline for 5 d after six LISTs. These suggest that fixture congestion induces greater muscle damage and performance decline than a single match.

Acute and Delayed Effects of Fatigue on Ground Reaction Force, Lower Limb Stiffness and Coordination Asymmetries During a Landing Task

Landing is a critical phase of movement for injury occurrence, in which lower limbs should be used equally to better absorb the shock. However, it has been suggested that fatigue can lead to the appearance of asymmetries. The aim of this study was to verify the acute and delayed effects of fatigue on the lower limb asymmetry indexes of peak ground reaction force, leg stiffness and intra-limb coordination during a landing task. Fifteen physically active men performed a fatigue protocol composed of 14 sets of 10 continuous vertical jumps, with a one-minute rest interval between the sets. A step-off landing task was performed before, immediately after, 24 h and 48 h after the fatigue protocol. Two force plates and a video analysis system were used. The symmetry index equation provided the asymmetry indexes. For statistical analysis, ANOVA and effect size analysis were utilized. Inferential statistics did not show the effect of fatigue in the asymmetry indexes for any variable or condition (p > .05). Moderate effect sizes were observed for peak ground reaction force (0.61) and leg stiffness (0.61) immediately after the application of the protocol. In conclusion, fatigue does not seem to significantly change the asymmetries of lower limbs, especially regarding intra-limb coordination. The moderate effects observed for peak ground reaction force and leg stiffness asymmetries suggest that these variables may be acutely affected by fatigue.

Progression of Fatigue Modifies Primary Contributors to Ground Reaction Forces During Drop Landing

Few studies have focused on the effect of fatigue severity on landing strategy. This study aimed to investigate the effect of fatigue progression on ground reaction force during landing. Eighteen participants performed a fatigue exercise protocol. Then participants performed drop landings at three levels of fatigue: no fatigue, medium fatigue, and severe fatigue. Multiple linear regression was conducted to identify the predictors of the peak vertical ground reaction force at each level of fatigue. Two-way ANOVAs were conducted to test the effect of fatigue on the vertical ground reaction force and the predictors. For the vertical ground reaction force, the knee joint stiffness and the knee angle at initial contact were the main predictors at no fatigue. The peak knee flexion angle and knee power were the main predictors at medium fatigue. However, the peak ankle plantarflexion moments became the main predictor at severe fatigue. The vertical ground reaction force decreased from no to medium fatigue (p = 0.001), and then increased from medium to severe fatigue (p = 0.034). The knee joint stiffness decreased from no to medium fatigue (p = 0.049), and then remained unchanged from medium to severe fatigue. The peak knee flexion angle increased from no to medium fatigue (p = 0.001), and then slightly decreased from medium to severe fatigue (p = 0.051). The results indicate that fatigue progression causes a transition from stiff to soft landing, and then to stiff landing. Participants used ankle joints more to control the landing intensity at severe fatigue.