The Effect of Selective Plyometric Training on the Lower Extremity Functional Performance Indexes of Female Athletes With Dynamic Knee Valgus

Context:The Lower-Extremity Functional Test (LEFT) has been used to assess readiness to return to sport after a lowerextremity injury. Current recommendations suggest that women should complete the LEFT in 135 s (average; range 120–150 s) and men should complete the test in 100 s (average; range 90–125 s). However, these estimates are based on limited data and may not be reflective of college athletes. Thus, additional assessment, including normative data, of the LEFT in sport populations is warranted.Objective:To examine LEFT times based on descriptive information and off-season training habits in NCAA Division III (DIII) athletes. In addition, this study prospectively examined the LEFT’s ability to discriminate sport-related injury occurrence.Design:Descriptive epidemiology.Setting:DIII university.Subjects:189 DIII college athletes (106 women, 83 men) from 15 teams.Main Outcome Measures:LEFT times, preseason questionnaire, and time-loss injuries during the sport season.Results:Men completed the LEFT (105 ± 9 s) significantly faster than their female counterparts (117 ± 10 s) (P < .0001). Female athletes who reported >3–5 h/wk of plyometric training during the off-season had significantly slower LEFT scores than those who performed ≤3 h/wk of plyometric training (P = .03). The overall incidence of a lower-quadrant (LQ) time-loss injury for female athletes was 4.5/1000 athletic exposures (AEs) and 3.7/1000 AEs for male athletes. Female athletes with slower LEFT scores (≥118 s) experienced a higher rate of LQ time-loss injuries than those with faster LEFT scores (≤117 s) (P = .03).Conclusion:Only off-season plyometric training practices seem to affect LEFT score times among female athletes. Women with slower LEFT scores are more likely to be injured than those with faster LEFT scores. Injury rates in men were not influenced by performance on the LEFT.

Download Full-text

The Effects of Eccentric and Plyometric Training Programs and Their Combination on Stability and the Functional Performance in the Post-ACL-Surgical Rehabilitation Period of Elite Female Athletes

Frontiers in Physiology ◽

10.3389/fphys.2021.688385 ◽

2021 ◽

Vol 12 ◽

Author(s):

Sofien Kasmi ◽

Hassane Zouhal ◽

Raouf Hammami ◽

Cain C. T. Clark ◽

Anthony C. Hackney ◽

...

Keyword(s):

Acl Reconstruction ◽

Female Athletes ◽

Functional Performance ◽

Training Programs ◽

Control Group ◽

Plyometric Training ◽

Significant Group ◽

Training Study ◽

Positive Effects ◽

Rehabilitation Period

BackgroundThe standard method to treat physically active patients with anterior cruciate ligament (ACL) rupture is ligament reconstruction surgery. The rehabilitation training program is very important to improve functional performance in recreational athletes following ACL reconstruction.ObjectivesThe aims of this study were to compare the effects of three different training programs, eccentric training (ECC), plyometric training (PLYO), or combined eccentric and plyometric training (COMB), on dynamic balance (Y-BAL), the Lysholm Knee Scale (LKS), the return to sport index (RSI), and the leg symmetry index (LSI) for the single leg hop test for distance in elite female athletes after ACL surgery.Materials and MethodsFourteen weeks after rehabilitation from surgery, 40 elite female athletes (20.3 ± 3.2 years), who had undergone an ACL reconstruction, participated in a short-term (6 weeks; two times a week) training study. All participants received the same rehabilitation protocol prior to the training study. Athletes were randomly assigned to three experimental groups, ECC (n = 10), PLYO (n = 10), and COMB (n = 10), and to a control group (CON: n = 10). Testing was conducted before and after the 6-week training programs and included the Y-BAL, LKS, and RSI. LSI was assessed after the 6-week training programs only.ResultsAdherence rate was 100% across all groups and no training or test-related injuries were reported. No significant between-group baseline differences (pre-6-week training) were observed for any of the parameters. Significant group-by-time interactions were found for Y-BAL (p < 0.001, ES = 1.73), LKS (p < 0.001, ES = 0.76), and RSI (p < 0.001, ES = 1.39). Contrast analysis demonstrated that COMB yielded significantly greater improvements in Y-BAL, LKS, and RSI (all p < 0.001), in addition to significantly better performances in LSI (all p < 0.001), than CON, PLYO, and ECC, respectively.ConclusionIn conclusion, combined (eccentric/plyometric) training seems to represent the most effective training method as it exerts positive effects on both stability and functional performance in the post-ACL-surgical rehabilitation period of elite female athletes.

Download Full-text

Instruction and Jump-Landing Kinematics in College-Aged Female Athletes Over Time

Journal of Athletic Training ◽

10.4085/1062-6050-48.2.09 ◽

2013 ◽

Vol 48 (2) ◽

pp. 161-171 ◽

Cited By ~ 20

Author(s):

Jena Etnoyer ◽

Nelson Cortes ◽

Stacie I. Ringleb ◽

Bonnie L. Van Lunen ◽

James A. Onate

Keyword(s):

Lower Extremity ◽

Retention Test ◽

Knee Flexion ◽

Female Athletes ◽

Initial Contact ◽

Knee Valgus ◽

Drop Jump ◽

Jump Landing ◽

Peak Knee ◽

Hip Flexion

Context: Instruction can be used to alter the biomechanical movement patterns associated with anterior cruciate ligament (ACL) injuries. Objective: To determine the effects of instruction through combination (self and expert) feedback or self-feedback on lower extremity kinematics during the box–drop-jump task, running–stop-jump task, and sidestep-cutting maneuver over time in college-aged female athletes. Design: Randomized controlled clinical trial. Setting: Laboratory. Patients or Other Participants: Forty-three physically active women (age = 21.47 ± 1.55 years, height = 1.65 ± 0.08 m, mass = 63.78 ± 12.00 kg) with no history of ACL or lower extremity injuries or surgery in the 2 months before the study were assigned randomly to 3 groups: self-feedback (SE), combination feedback (CB), or control (CT). Intervention(s): Participants performed a box–drop-jump task for the pretest and then received feedback about their landing mechanics. After the intervention, they performed an immediate posttest of the box–drop-jump task and a running–stop-jump transfer test. Participants returned 1 month later for a retention test of each task and a sidestep-cutting maneuver. Kinematic data were collected with an 8-camera system sampled at 500 Hz. Main Outcome Measure(s): The independent variables were feedback group (3), test time (3), and task (3). The dependent variables were knee- and hip-flexion, knee-valgus, and hip- abduction kinematics at initial contact and at peak knee flexion. Results: For the box–drop-jump task, knee- and hip-flexion angles at initial contact were greater at the posttest than at the retention test (P < .001). At peak knee flexion, hip flexion was greater at the posttest than at the pretest (P = .003) and was greater at the retention test than at the pretest (P = .04); knee valgus was greater at the retention test than at the pretest (P = .03) and posttest (P = .02). Peak knee flexion was greater for the CB than the SE group (P = .03) during the box–drop-jump task at posttest. For the running–stop-jump task at the posttest, the CB group had greater peak knee flexion than the SE and CT (P ≤ .05). Conclusions: Our results suggest that feedback involving a combination of self-feedback and expert video feedback with oral instruction effectively improved lower extremity kinematics during jump-landing tasks.

Download Full-text

What Is the Most Effective Training Approach for Preventing Noncontact ACL Injuries in High School–Aged Female Athletes?

Journal of Sport Rehabilitation ◽

10.1123/jsr.2017-0055 ◽

2019 ◽

Vol 28 (1) ◽

pp. 94-98 ◽

Cited By ~ 2

Author(s):

Erica M. Willadsen ◽

Andrea B. Zahn ◽

Chris J. Durall

Keyword(s):

Knee Flexion ◽

Female Athletes ◽

Balance Training ◽

Core Stability ◽

Knee Valgus ◽

Plyometric Training ◽

Acl Injuries ◽

Training Approach ◽

Effective Training ◽

Stability Training

Clinical Scenario: A variety of training approaches have been adopted in anterior cruciate ligament (ACL) prevention programs, including neuromuscular control training, core stability training, balance training, and plyometric exercise. This review was conducted to determine if current evidence supports one of these training approaches over the others for reducing noncontact ACL injuries in adolescent female athletes. Focused Clinical Question: What is the most effective training approach for preventing noncontact ACL injuries in adolescent and/or high school–aged female athletes? Summary of Key Findings: A literature search generated 2 level 1b randomized control trials and 1 level 2b cohort study. Plyometric training resulted in decreased knee valgus during landing in 3 studies and increased knee flexion at landing in 2 studies. Balance training or neuromuscular training led to decreased knee valgus and increased knee-flexion angles with landing in 2 studies. Core stability training had conflicting effects on knee valgus and knee-flexion angles at landing, with 1 study reporting no effect and another reporting an undesirable decrease in knee joint flexion angle at landing. Clinical Bottom Line: Based on this review, plyometric training, balance training, and neuromuscular training approaches appear sensible to include in ACL prevention programs for female athletes to help decrease knee valgus and knee flexion during landing. Core stability training may be somewhat beneficial for decreasing knee valgus angles at landing, although may have nominal or even deleterious effects on knee-flexion angle at landing, and thus should be implemented with caution. Strength of Recommendation: Our recommendations were derived from the results of 2 level 1b randomized control trials and 1 level 2b cohort study.

Download Full-text

Lower extremity energy absorption strategies at different phases during single and double-leg landings with knee valgus in pubertal female athletes

Scientific Reports ◽

10.1038/s41598-021-96919-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mahdis Dadfar ◽

M. Soltani ◽

Mohammadreza Basohbat Novinzad ◽

Kaamran Raahemifar

Keyword(s):

Lower Extremity ◽

Energy Absorption ◽

Female Athletes ◽

Mechanical Energy ◽

Pearson Correlation ◽

Plantar Flexion ◽

Knee Extensors ◽

Initial Contact ◽

Knee Valgus ◽

Plantar Flexors

AbstractDynamic knee valgus (DKV) malalignment affects the biomechanical characteristic during sports activities. This cross-sectional study was conducted to evaluate mechanical energy absorption (MEA) strategies at initial contact (IC) and total landing (TL) phases during single-leg landing (SLL), and double-leg landing (DLL). Twenty-eight female athletes with DKV (age 10–14) were invited. MEA analysis of lower extremity joints was done in sagittal and frontal motion planes employing 8 Vicon motion capture cameras and 2 Kistler force plates. Statistical analysis was done using IBM Statistics (version24) by Bivariate Pearson Correlation Coefficient test. Knee extensors MEA during SLL (IC: P = 0.008, R = 0.522/TL: P < 0.001, R = 0.642) and DLL (IC: P < 0.001, R = 0.611/TL: P = 0.011, R = 0.525), and knee abductors during SLL (IC: P = 0.021, R = 0.474) were positively correlated with increased DKV angle. Ankle plantar flexors during SLL (TL: P = 0.017, R = − 0.477) and DLL (TL: P = 0.028, R = − 0.404), and hip extensors during SLL (TL: P = 0.006, R = − 0.5120) were negatively correlated with increased DKV angle. Compensated MEA in knee extensors was correlated with less ankle plantar flexion MEA during SLL (IC: P = 0.027, R = − 0.514/TL: P = 0.007, R = − 0.637) and DLL (IC: P = 0.033, R = − 00.412/TL: P = 0.025, R = − 0.485). These outcomes indicated a knee-reliant MEA strategy in female athletes with DKV during puberty, putting them at higher risks of ACL injuries during landing.

Download Full-text

Effect of Resisted Sprint and Plyometric Training on Lower Limb Functional Performance in Collegiate Male Football Players: A Randomised Control Trial

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18136702 ◽

2021 ◽

Vol 18 (13) ◽

pp. 6702

Author(s):

Shahnaz Hasan ◽

Gokulakannan Kandasamy ◽

Danah Alyahya ◽

Asma Alonazi ◽

Azfar Jamal ◽

...

Keyword(s):

Functional Performance ◽

Group Analysis ◽

Training Group ◽

Control Group ◽

Football Players ◽

Plyometric Training ◽

Sprint Training ◽

Short Term ◽

Hop Test ◽

Collegiate Football

The main objectives of this study were to evaluate the short-term effects of resisted sprint and plyometric training on sprint performance together with lower limb physiological and functional performance in collegiate football players. Ninety collegiate football players participated in this three-arm, parallel group randomized controlled trial study. Participants were randomly divided into a control group and two experimental groups: resisted sprint training (RST) (n = 30), plyometric training (PT) (n = 30), and a control group (n = 30). Participants received their respective training program for six weeks on alternate days. The primary outcome measures were a knee extensor strength test (measured by an ISOMOVE dynamometer), a sprint test and a single leg triple hop test. Measurements were taken at baseline and after 6 weeks post-training. Participants, caregivers, and those assigning the outcomes were blinded to the group assignment. A mixed design analysis of variance was used to compare between groups, within-group and the interaction between time and group. A within-group analysis revealed a significant difference (p < 0.05) when compared to the baseline with the 6 weeks post-intervention scores for all the outcomes including STN (RST: d = 1.63; PT: d = 2.38; Control: d = 2.26), ST (RST: d = 1.21; PT: d = 1.36; Control: d = 0.38), and SLTHT (RST: d = 0.76; PT: d = 0.61; Control: d = 0.18). A sub-group analysis demonstrated an increase in strength in the plyometric training group (95% CI 14.73 to 15.09, p = 0.00), an increase in the single leg triple hop test in the resisted sprint training group (95% CI 516.41 to 538.4, p = 0.05), and the sprint test was also improved in both experimental groups (95% CI 8.54 to 8.82, p = 0.00). Our findings suggest that, during a short-term training period, RST or PT training are equally capable of enhancing the neuromechanical capacities of collegiate football players. No adverse events were reported by the participants.

Download Full-text

Differences in strength and landing biomechanics between female jumpers and swimmers

Isokinetics and Exercise Science ◽

10.3233/ies-210149 ◽

2021 ◽

pp. 1-11

Author(s):

Mianfang Ruan ◽

Qiang Zhang ◽

Xin Zhang ◽

Jing Hu ◽

Xie Wu

Keyword(s):

Muscle Force ◽

Female Athletes ◽

Young Female ◽

Single Component ◽

Plyometric Training ◽

Isokinetic Testing ◽

Female College ◽

Landing Biomechanics ◽

Drop Landing ◽

Landing Mechanics

BACKGROUND: It remains unclear if plyometric training as a single component could improve landing mechanics that are potentially associated with lower risk of ACL injury in the long term OBJECTIVE: The purpose of this study was to investigate the influence of experience undertaking plyometrics on landing biomechanics in female athletes. METHODS: Non-jumpers with little experience in plyometric training (12 female college swimmers) and jumpers with five years of experience in plyometric training (12 female college long jumpers and high jumpers) were recruited to participate in two testing sessions: an isokinetic muscle force test for the dominant leg at 120∘/s and a 40-cm drop landing test. An independent t test was applied to detect any significant effects between cohorts for selected muscle force, kinematic, kinetic, and electromyography variables. RESULTS: While female jumpers exhibited greater quadriceps eccentric strength (P= 0.013) and hamstring concentric strength (P= 0.023) during isokinetic testing than female swimmers, no significant differences were observed in kinematics, kinetics, and muscle activities during both drop landing and drop jumping. CONCLUSIONS: The results suggest that the female jumpers did not present any training-induced modification in landing mechanics regarding reducing injury risks compared with the swimmers. The current study revealed that plyometric training as a single component may not guarantee the development of low-risk landing mechanics for young female athletes.

Download Full-text

Hip and ankle strength and range of motion in female soccer players with dynamic knee valgus

Isokinetics and Exercise Science ◽

10.3233/ies-200260 ◽

2021 ◽

pp. 1-6

Author(s):

Young Jin Jo ◽

Young Kyun Kim

Keyword(s):

Range Of Motion ◽

Female Athletes ◽

External Rotation ◽

Preventive Measure ◽

Control Group ◽

Knee Valgus ◽

Strength Ratio ◽

Flexion Extension ◽

Hip Abduction ◽

Single Leg Squat

BACKGROUND: Dynamic knee valgus (DKV) is a known risk factor for acute and chronic knee injuries and is more frequently diagnosed in females. A real-time single-leg squat test (SLST) could screen for DKV to prevent injuries. OBJECTIVE: To compare the differences in lower extremity strength and range of motion (ROM) in female soccer athletes with and without DKV during an SLST. METHODS: Eighteen subjects with DKV (DKV group) and 18 subjects without DKV (control group) during a single-leg squat were included. Hip strength (flexion, extension, abduction, adduction, internal rotation, and external rotation) was measured with a hand-held dynamometer. Hip ROM (internal and external rotation), and ankle ROM (dorsiflexion with the knee flexed and extended) were measured. Independent t-test was used to compare the averages of the groups. RESULTS: There were significant differences in hip abduction to adduction strength ratio (DKV: 1.48 ± 0.3, control: 1.22 ± 0.26, p< 0.01) and ankle dorsiflexion with knee flexed (DKV: 17.22 ± 6.82, control: 21.22 ± 4.55, p< 0.05) and extended (DKV: 10.14 ± 4.23, control: 14.75 ± 3.40, p< 0.001) between the groups. CONCLUSION: The hip abduction to adduction strength ratio and gastrocnemius and soleus flexibility may be associated factors in dynamic knee valgus and therefore should be assessed and treated, if indicated, as a possible preventive measure in female athletes with this variation.

Download Full-text