Longitudinal assessments of balance and jump-landing performance before and after anterior cruciate ligament injuries in collegiate athletes

The effectiveness of the STOP-X training program on the knee valgus angle and balance in female basketball players with dynamic knee valgus: a randomized controlled trial

BACKGROUND

Dynamic knee valgus (DKV) accompanied by poor balance is the cause of anterior cruciate ligament (ACL) injury in athletes, and the identification and correction of these factors are always of interest to researchers. Therefore, the purpose of this research was to investigate the effect of the STOP-X program on the knee valgus angle and static and dynamic balance in female basketball players with DKV defects.

METHODS

The present study was a quasi-experimental study. Thirty female basketball players with DKV defects were purposefully identified by the single-leg landing (SLL) test and were randomly assigned to two control (n = 15) and experimental (n = 15) groups. Static balance status was evaluated with the BASS STICK test, and dynamic balance status was evaluated with the Y-balance test (YBT). The experimental group performed the STOP-X program for 25-40 min for eight weeks (three times per week), and the control group performed their traditional warm-up program. Data were analyzed by means of 2 × 2 repeated measures ANOVA followed by post hoc comparison (Bonferroni) at the significance level of (P < 0.05) with SPSS version 26.

RESULTS

The results showed that with the use of the STOP-X program, there was a significant difference between the experimental and control groups in variables of the static balance (F = 56.45; P = 0.001; ES = 0.66, PC=↑59.64%), total dynamic balance score (F = 107.57; P = 0.001; ES=↑0.79, PC=↑19.84%), and knee valgus angle (F = 119.46; P = 0.001; ES = 0.81, PC=↓34.36%).

CONCLUSION

In addition to reducing the knee valgus angle, applying the STOP-X injury prevention program can improve static and dynamic balance in female basketball players with DKV defects. Therefore, it can be recommended that sports trainers benefit from these advantages by adding STOP-X training to routine basketball exercises.

Association between quadriceps muscle thickness and knee function in anterior cruciate ligament reconstructed athletes: a cross-sectional study

OBJECTIVE

This study aimed to investigate the association between vastus medialis obliquus (VMO), rectus femoris (RF), and vastus lateralis (VL) muscle thickness and quadriceps isokinetic strength, single-leg hop performance, and self-reported knee function in male athletes who had undergone anterior cruciate ligament reconstruction (ACLR).

METHODS

Forty-two male athletes [mean ± standard deviation, age: 21.4 ± 3.4 years], who had undergone ACLR and had cleared to return to activity, were included in this study. Real-time ultrasound images of VMO, RF, and VL thicknesses were obtained from both reconstructed and contralateral limbs. Concentric quadriceps peak torque at 60°/s and 180°/s, single-leg hop for Distance (SLHD), and self-reported knee function scores were also assessed. Linear regression analysis and student t tests were used for statistical analysis.

RESULTS

In reconstructed limb, greater VMO, RF, and VL thicknesses were associated with greater quadriceps peak torque at 60°/s (p = .008, r2 = 0.46) and at 180°/s (p = .006, r2 = 0.47). Greater quadriceps thickness was related to greater SLHD score in reconstructed limb (p = .002, r2 = 0.21). Self-reported knee function scores were not related to quadriceps thickness. VMO, RF, and VL thicknesses were smaller in reconstructed limb compared to contralateral limb (p < .001, p = .01, and p = .002, respectively).

CONCLUSION

Quadriceps thickness by using ultrasound was associated with concentric quadriceps strength and single-leg hop distance in individuals who had undergone ACLR. However, quadriceps thickness was not related to self-reported knee function. The ultrasonography may be included in the evaluation of the knee function after ACLR, and it may be a useful and easy method in the follow-up of the quadriceps strength recovery following ACLR.

Jump-landing kinetic asymmetries persisted despite symmetric squat kinetics in collegiate athletes following anterior cruciate ligament reconstruction

The purpose was to determine the differences/correlations in anterior cruciate ligament (ACL) loading variables and bilateral asymmetries between injured/uninjured legs and among ascending/descending phases of double-leg squats and jumping/landing phases of countermovement jumps (CMJ) in the collegiate athletes following ACL reconstruction (ACLR). Fourteen collegiate athletes performed squats and CMJ 6-14 months following ACLR. The bilateral knee/hip flexion angles, peak vertical ground reaction force (VGRF) and knee extension moments (KEM), and kinetic asymmetries were calculated. Squats showed the greatest knee/hip flexion angles, while the landing phase of CMJ showed the least (P<0.001). The uninjured leg demonstrated greater VGRF (P≤0.010) and KEM (P≤0.008) than the injured leg in CMJ. Kinetic asymmetries were less than 10% for squats but were greater for the jumping (P≤0.014, 12%-25%) and landing (P≤0.047, 16%-27%) phases of CMJ. Significant correlations were found for KEM asymmetries between phases of CMJ (P=0.050) and squats (P<0.001). Kinetic asymmetries persisted in CMJ, while kinetic symmetries were achieved in squats in collegiate athletes 6-14 months following ACLR. Therefore, the CMJ appears to be a more sensitive assessment to monitor the bilateral kinetic asymmetries compared to squats. It is suggested to assess and screen kinetic asymmetries in different phases and tasks.

Longitudinal assessments of strength and dynamic balance from pre-injury baseline to 3 and 4 months after labrum repairs in collegiate athletes

BACKGROUND

There is a lack of quantitative assessments of athletes' functional strength and dynamic balance following labrum repairs.

PURPOSE

To compare the upper extremity strength and dynamic balance among pre-injury baseline and approximately 3 and 4 months after labrum surgeries in collegiate athletes to identify critical values to inform rehabilitation.

METHODS

Fifteen male and one female collegiate athletes between 18 and 22 years old were tested at pre-injury baseline (n = 14) and 2.7 (n = 16) and 3.8 months (n = 12) after labrum surgeries. Strength was assessed using the peak forces produced in a maximal push-up test. Dynamic balance was assessed using the reaching distances in a reaching test.

RESULTS

The injured side's peak forces significantly decreased from the baseline to the 3-month post-surgery and then significantly increased between the 3-month and 4-month post-surgery assessments but remained significantly less at the 4-month post-surgery compared to the baseline (p ≤ 0.024; Cohen's dz ≥ 0.75). Peak force asymmetries were greater at the 3-month and 4-month post-surgery assessments than the baseline (p ≤ 0.005; Cohen's dz ≥ 1.02).

CONCLUSION

With a relatively small sample size, the results support the use of objective functional assessments for rehabilitation and return-to-play decisions among collegiate athletes following labrum repairs.

Return to play in elite rugby players after severe knee injuries

Background

Medical professionals working in an elite sport environment have the challenging task to balance the athlete's readiness to return to the playing field after severe injury with other stakeholders' (coaches, sponsors, teammates) opinions and objectives.

Objectives

Our study aimed to evaluate differences in the physical profiles of elite rugby players at return to play (RTP) after a severe knee injury, compared with their pre-injury profiles and matched controls.

Method

Before the injury, participants performed four performance tests during their preseason screening. These tests were repeated and compared to baseline once a player was declared fit to play.

Results

Significant differences (p ≤ 0.05) were found in the injured players' group who were slower over 10 m speed, in their decision-making time and the total time of the reactive agility tests at RTP, whilst controls were significantly faster over 10 m and 30 m speed tests. The countermovement jump outcomes showed significant improvement in the uninjured participants (p ≤ 0.05).

Conclusion

Our study highlights that injured players' running speeds and decision-making times are slower after injury. The uninjured players have a positive outcome to training and match stimulus by improving their running speed and lower body explosive power during the season.

Clinical implications

Our study provides insight into the RTP profile of elite rugby players, and a novel finding was the decision-making time deficit. This highlights the importance of cognitive training during injury rehabilitation as athletes make numerous decisions in a pressured and uncontrolled environment during a match. Speed training development is recommended as the athletes were slower after severe knee injury.

Strong, Fast, Fit, Lean, and Safe: A Positional Comparison of Physical and Physiological Qualities Within the 2020 Australian Women's Rugby League Team

ABSTRACT

Minahan, C, Newans, T, Quinn, K, Parsonage, J, Buxton, S, and Bellinger, P. Strong, Fast, Fit, Lean, and Safe: A positional comparison of physical and physiological qualities within the 2020 Australian Women's Rugby League team. J Strength Cond Res 35(12S): S11-S19, 2021-The purpose of the present study was to report the physical and physiological characteristics of elite women Rugby League (RL) players. Thirty-nine women (25.6 ± 4.3 years, 171.3 ± 7.7 cm, 83.5 ± 13.9 kg) from the 2020 Australian women's RL squad were recruited for this study. Players were categorized as adjustables (n = 7), backs (n = 15), or forwards (n = 17) for analysis. Each player was assessed for anthropometry, body composition (dual-energy X-ray absorptiometry), speed (5, 10 and 20 m sprint times), lower-body power (countermovement jump), upper-body power (medicine ball throw and explosive push up force), estimated one repetition maximum (e1RM) bench press, squat and bench pull, isometric mid-thigh pull strength, eccentric knee flexor strength, isometric hip abduction and adduction, and intermittent endurance performance (30-15 intermittent fitness test; 30-15 IFT). Linear mixed models were performed to compare positional groups. Forwards were significantly heavier and had greater fat mass, fat-free mass, and body fat percentage compared with backs and adjustables (P < 0.01). Backs were faster over 20 m compared with forwards (P = 0.025), whereas forwards had a lower 30-15 IFT peak velocity and estimated V̇o2peak compared with backs and adjustables. Nonetheless, when including body mass in the model, there were no differences between groups in 30-15 IFT peak velocity. There were no significant differences in other variables. These results provide contemporary benchmark physical, physiological, and anthropometric data for elite women RL players, which can inform recruitment, selection, training, and testing.

Neuromuscular and biomechanical landing alterations persist in athletes returning to sport after anterior cruciate ligament reconstruction

BACKGROUND

Anterior cruciate ligament reconstructed (ACLR) athletes show increased hamstrings activation and decreased knee flexion moments (KFMs) during single leg landing tasks at time of return-to-sport (RTS). Although these landing alterations seem protective in the short term, they might become undesirable if they persist after RTS. Therefore, the main aim of this study was to investigate whether those landing alterations persist in the months following RTS.

METHODS

Sixteen athletes who had an ACLR performed five unilateral landing tasks at three different time points (at RTS, and at 3 and 6 months after RTS) while KFMs and hamstrings activation were recorded. The following clinical parameters were registered: isokinetic strength of quadriceps and hamstrings, ACL return-to-sport after injury scale (ACL-RSI), Tampa scale of kinesiophobia, self-reported instability and single leg hop distance. A one-way repeated measures analysis of variance (ANOVA) was used to assess whether landing deficits changed over time. Additionally, an explorative analysis was performed to assess whether those athletes whose deficits persisted the most could be identified based on baseline clinical parameters.

RESULTS

The ANOVA showed no differences in landing deficits between sessions, indicating persisting reduced KFMs and increased hamstrings activation in the injured leg compared with the contralateral leg. A significant improvement of the quadriceps concentric strength (at 120°/s), ACL-RSI score and jump distance of the single leg hop was found over time.

CONCLUSIONS

Landing alterations were not resolved 6 months after RTS. Additional interventions may be needed to normalize landing alterations prior to return to sport.

Medial-lateral hip positions predicted kinetic asymmetries during double-leg squats in collegiate athletes following anterior cruciate ligament reconstruction

ACL re-injury rates are high in collegiate athletes, and double-leg squats have been used as a functional weight-bearing exercise to strengthen the lower extremities and assess bilateral kinetic asymmetries. The primary purpose was to quantify the correlations between medial-lateral shoulder/hip positions and lateral bending angles and bilateral asymmetries in vertical ground reaction forces (VGRF) and knee extension moments during double-leg squats in collegiate athletes at two assessments following anterior cruciate ligament reconstruction (ACLR). Seventeen National Collegiate Athletic Association Division I athletes performed double-leg squats between 0 and 6 months and/or between 6 and 12 months following their ACLR while kinematic and kinetic data were collected. Medial-lateral shoulder positions strongly and significantly correlated with VGRF asymmetries at both assessments (p ≤ 0.007, r ≥ 0.68). Medial-lateral hip positions strongly and significantly correlated with VGRF asymmetries and knee moment asymmetries at both assessments (p ≤ 0.018, r ≥ 0.62). Additionally, participants demonstrated decreased VGRF asymmetries and knee moment asymmetries, more neutral shoulder and hip positions, and increased knee moments for the injured leg at the second assessment compared to the first assessment with large effect sizes (p ≤ 0.008, Cohen's d ≥ 1.06). In conclusion, medial-lateral hip positions correlated and predicted VGRF and knee moment asymmetries during double-leg squats in collegiate athletes at two assessments (0-6 and 6-12 months) following ACLR. The bilateral asymmetries support the need for an individual approach for kinetic asymmetry assessments. A commercially available camera can be utilized as a low-cost and convenient tool to monitor and potentially train bilateral kinetic symmetries during double-leg squats in patients following ACLR.