Tibiofemoral Joint Loading During a Landing Task After Strength Training

Research Review: Strength Training Intervention and Its Effects on Tibiofemoral Loading During Landing

By Tristan J. Rodik, M.AT., ATC

Edited By Brent Brookbush, DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Czasche, M. B., Goodwin, J. E., Bull, A. M. J. and Cleather, D. J. (2018) Effects of an 8-week strength training intervention on tibiofemoral joint loading during landing: a cohort study. BMJ Open Sport & Exercise Medicine, 4(1), doi: 10.1136/bmjsem-2017-000273. Full Article

Why the Study is Relevant: Prior research has demonstrated that exercise programs designed to improve knee alignment, such as a functional knee valgus, may help reduce the incidence of anterior cruciate ligament (ACL) injuries (1-7). This 2018 study demonstrated that strengthening of the glute complex (gluteus medius and gluteus maximus ) and hamstrings resulted in a decrease in lateral load and increase in medial load at the knee during landing, which is consistent with a reduction in knee valgus. The findings of this study imply that human movement professionals may consider integrating glute complex and hamstring exercises to reduce the occurrence of ACL injuries.

Caption: Practicing Hop Down to Single Leg Touch Down in the Transverse Plane with a Soft Landing

Practicing Hop Down to Single Leg Touch Down in the Transverse Plane with a Soft Landing

Study Summary

Study Design	Cohort Study
Level of Evidence	IIB Evidence from at least one other type of quasi-experimental study
Participant Characteristics	Demographics Intervention Group: Participants: 8 Gender: Female Age: 22.0 +/- 3.2 Body Mass: 65.4 +/- 7.1 kg Height: 1.68 +/- 0.03 m Control Group: Participants: 8 Gender: Female Age: 22.9 +/- 3.2 Body Mass: 62.2 +/- 8.3 kg Height: 1.66 +/- 0.07 m Inclusion Criteria: Female Ages 18-28 No musculoskeletal injuries in the previous 6 months Right foot dominant Recreationally active Leisure sport participation of no more than 4x/week Exclusion Criteria: Participated in a resistance training program or injury prevention program over the previous 6 months
Methodology	Pre-Intervention Testing: Participants performed a 10-minute dynamic warm-up Participants practiced the drop landing task (no more than 5 trials) Bilateral and unilateral practice trials During a 3-5-minute rest period, reflective markers were placed on anatomical landmarks The drop landing task consisted of a 30cm platform placed 0.5 cm in front of the force plate Participants completed 5 bilateral landings, then 5 unilateral landings on the dominant extremity After a 3-5-minute rest period strength testing was conducted for hip extension Participants assumed a supine position, with the hip flexed to 30 degrees and the ankle in neutral alignment. They were instructed to push the heel down on a force plate. Exercise Intervention (Intervention Group): 8-week posterior leg strength training program 1-hour sessions, 3x/week Common glute complex (gluteus maximus and gluteus medius) and hamstring dominant exercises were used Weight was progressed each week based on individual responses Sets, reps, rest and rating of perceived exertion remained constant Post-Intervention Testing: Identical to pre-intervention testing
Data Collection and Analysis	FreeBody software (www.msksoftware.org.uk) was used to compare pre-intervention and post-intervention muscle and joint reaction force data Markers determined positioning of the pelvis, thigh, calf and foot A fourth-order dual low-pass Butterworth filter of 6 Hz was used to filter kinematic and kinetic data, which were processed through the FreeBody software Statistical analysis using SPSS (V.22; International Business Machines, Armonk, NY, USA) and MATLAB (R2013a; Mathworks) ANOVA assessed differences in age and anthropometry among groups ANCOVA assessed changes in strength of right hip extension Significance was set to p < 0.05 Shapiro-Wilk testing confirmed normality
Outcome Measures	Ground reaction force of the drop landing task Hip extension strength testing results Knee joint contact forces
Results	Intervention group (IG) participants attended 94% of planned sessions The IG improved hip extension strength by 35% The control group (CG) demonstrated no change in strength In pre-testing, all participants demonstrated more lateral knee joint contact force than medial force For post-testing, the IG demonstrated: Lateral knee joint contact forces that were lower than medial contact forces during the bilateral drop landing task Lateral knee joint contact forces were greater than medial contact forces during the unilateral drop landing task Ground reaction forces slightly increased for both groups during the bilateral drop landing task The control group demonstrated marginally lower ground reaction forces during post-testing for the unilateral drop landing task There was no change noted in kinematic variables when comparing pre-test and post-test results among both groups
Our Conclusions	The findings reveal that the IG group experienced a decrease in lateral force and increase in medial force knee joint forces. This suggests that glute complex and hamstring strengthening in active women will help develop favorable knee force distribution.
Researchers' Conclusions	Posterior thigh strengthening increases use of the gluteal musculature during a drop landing task. Knee joint contact forces shifted from a lateral to medial emphasis. This change is indicative of reduced knee valgus and an increased hip joint loading pattern.

Caption: Robert Griffin III during a vertical jump test his rookie year. Note his knees bow in, a.k.a. functional valgus.

Robert Griffin III during a vertical jump test his rookie year. Note his knees bow in, a.k.a. functional valgus.

Why This Study is Important:

This study adds to a growing body of research supporting the use of glute complex strengthening to improve lower-extremity biomechanics (8-14). Unique to this study, the authors used musculoskeletal modelling to estimate medial and lateral internal knee joint loads during unilateral and bilateral landing pre- and post intervention. The intervention used in this study was 8 weeks glute complex and hamstring strengthening. The findings of this study imply that intervention resulted in a decrease in lateral load and increase in medial load (more balanced force distribution). This may imply that glute complex and hamstring strengthening has the potential to reduce the risk of knee injury.

How the Findings Apply to Practice:

Human movement professionals should consider incorporating glute complex and hamstring strengthening into the program of any individual at risk of knee injury during daily activity and sport. Note: Although the Brookbush Institute (BI) recommends glute complex strengthening, it does not recommend specific strengthening exercises for the hamstrings (described below). Further, this study demonstrated that it may be necessary to incorporate and progress several exercises, over several weeks to make considerable change. Further research is needed to determine minimum and maximum volumes.

This study had many methodological strengths, including:

The use of common strengthening exercises for the glute complex and hamstrings including lunges , Nordic hamstring curls , glute bridges , step-ups , and squats , improves applicability.
The drop landing task included bilateral and unilateral landings, which are both seen in sport resulting in anterior cruciate ligament injuries.
Compliance among members of the intervention group was high, with 94% attendance of strengthening sessions further strengthening statistical analysis of the data.
This study used musculoskeletal modelling to estimate internal knee joint forces, which provided a greater understanding of medial and lateral joint loading.

Weaknesses that should be noted prior to clinical integration:

All participants were recreationally active, right-foot dominant females, which may limit generalizability to sedentary and/or male populations.
The small sample size, 16 participants, may have impacted the statistical significance of the results.
Hip strength testing was assessed using a force plate, which may limit practical application of findings.
Gluteal measures during the drop landing task were measured via ground reaction forces and not directly through electromyography analysis

How This Study Related to Brookbush Institute Content:

The Brookbush Institute (BI) uses an integrated approach to address Lower Extremity Dysfunction (LED) , Lumbo-pelvic Hip Complex Dysfunction (LPHCD) and Sacroiliac Joint Dysfunction (SIJD) . Any one or a combination of these dysfunctions may result in the altered pattern noted in this study, knee valgus during landing. Although this study provides evidence for the use of gluteus maximus , gluteus medius and hamstring strengthening to address this altered movement pattern, the BI does not support the use of specific (single joint) hamstring strengthening. As noted in the models above (LED , LPHCD , SIJD ), the hamstrings , especially the biceps femoris , are prone to over-activity and synergistic dominance for an inhibited/under-active gluteus maximus and gluteus medius . Therefore, the Nordic hamstring exercise and hamstring curls are not recommended by the BI. Integrated (multi-joint) triple extension exercises like lunges , glute bridges , step-ups , and squats , are recommended after addressing under-active muscles with isolated activation techniques.

Functional Anatomy of the Gluteus Maximus and Gluteus Medius

Gluteus Maximus Manual Muscle Testing

Glute Activation Circuit

Ultimate Glute Bridge

Static Lunge to Row

Tibiofemoral Joint Loading During a Landing Task After Strength Training

Research Review: Strength Training Intervention and Its Effects on Tibiofemoral Loading During Landing

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