A resistance band increased internal hip abduction moments and gluteus medius activation during pre-landing and early-landing

The Use of Elastic Resistance Bands to Reduce Dynamic Knee Valgus in Squat-Based Movements: A Narrative Review

An elastic band wrapped around the distal thighs has recently been proposed as a method for reducing dynamic knee valgus (medial movement of the knee joint in the frontal/coronal plane) while performing squats. The rationale behind this technique is that, by using an external force to pull the knees into further knee valgus, the band both exaggerates the pre-existing movement and provides additional local proprioceptive input, cueing individuals to adjust their knee alignment. If these mechanisms are true, then elastic bands might indeed reduce dynamic knee valgus, which could be promising for use in injury prevention as excessive knee valgus may be associated with a greater risk of sustaining an ACL rupture and/or other knee injuries. Due to this possibility, certain athletic populations have already adopted the use of elastic bands for training and/or rehab, despite a limited number of studies showing beneficial findings. The purpose of this narrative review is to examine current literature that has assessed lower limb muscle activity and/or lower limb kinematics performance on squat-based movements with or without an elastic band(s). Importantly, this paper will also discuss the key limitations that exist in this area, propose suggestions for future research directions, and provide recommendations for training implementations.

Level of Evidence

5.

Sex Difference in Lower-limb Electromyography and Kinematics when Using Resistance Bands during a Barbell Back Squat

The aim of this study was to compare the muscle activity of the gluteus medius (GMe), gluteus maximus (GMa), biceps femoris (BF), vastus lateralis (VL), vastus medialis (VM) and erector spinae (ES) as well as medial knee displacement (MKD) while using varying stiffness resistance bands (red: 1.68 kg; black: 3.31 kg; gold: 6.44 kg) during a barbell back squat (BBS) among males and females. A total of 23 (females: 11) resistance trained people were recruited for this study. Muscle activity was measured using electromyography, and motion capture cameras tracked lower-limb kinematics and MKD. Three resistance bands were placed at the distal end of the femur while performing a BBS at their 85% repetition maximum (RM). Parametric and non-parametric statistical analyses were conducted with the alpha level of 0.05. The gold resistance band resulted in a smaller knee-width-index value (i.e., greater MKD) compared to other bands (p < 0.01). Males exhibited less MKD compared to females during the BBS for each resistance band (p = 0.04). Males produced greater VL activity when using the black and gold resistance bands during the BBS (p = 0.03). When using a gold resistance band, the GMe muscle activation was higher compared to other resistance bands (p < 0.01). VM muscle activity was reduced when using a gold resistance band compared to no band condition (p < 0.01). BF (p = 0.39) and ES (p = 0.88) muscle activity did not change when using different resistance bands. As a result, females may be at a biomechanical disadvantage when using resistance bands compared to males while performing the BBS hindering them from optimal performance.

The influence of gluteal muscle strength deficits on dynamic knee valgus: a scoping review

Anterior cruciate ligament (ACL) injuries are caused by both contact and non-contact injuries. However, it can be claimed that non-contact ones account approximately for 70% of all cases. Thus, several authors have emphasized the role of reduction of muscle strength as a modifiable risk factor referred to non-contact ACL injury, with the latter being targeted by specific training interventions.The present paper wants to review the available literature specifically on the relationship between dynamic knee valgus, gluteal muscles (GM) strength, apart from the potential correlation regarding ACL injury.After a research based on MEDLINE via PubMed, Google scholar, and Web of Science, a total of 29 articles were collected and thus included.Additionally, this review highlights the crucial role of gluteal muscles in maintaining a correct knee position in the coronal plane during different exercises, namely walking, running, jumping and landing.

Effects of an elastic resistance band exercise program on kinetics and muscle activities during walking in young adults with genu valgus: A double-blinded randomized controlled trial

BACKGROUND

This double-blinded randomized-controlled-trial aimed to identify the effects of an elastic band resistance training on walking kinetics and muscle activities in young adults with genu valgus.

METHODS

Forty-two male young adults aged 22.5(2.7) years with genu valgus were randomly allocated to two experimental groups. The intervention group (n = 21) conducted a 14-weeks elastic band resistance training. The control group was passive during the intervention period and received the same treatment after the post-tests. Pre and post training, ground reaction forces and lower limb muscle activities were recorded during walking.

FINDINGS

Results revealed significant group-by-time interactions for peak medial ground reaction force and time-to-peak for posterior ground reaction force in favor of the intervention group (p < 0.012; d = 0.83-3.76). Resistance training with elastic bands resulted in significantly larger peak medial ground reaction force (p < 0.001; d = 1.45) and longer time-to-peak for posterior ground reaction force (p < 0.001; d = 1.85). Finding showed significant group-by-time interactions for peak positive free moment amplitudes in favor of the intervention group (p < 0.001; d = 1.18-2.02). Resistance training resulted in a lower peak positive free moment amplitude (p = 0.001; d = 1.46). With regards to muscle activities, the analysis revealed significant group-by-time interactions for rectus femoris and gluteus medius activities during the push-off phase in favor of the intervention group (p < 0.038; d = 0.68-0.89). Resistance training induced higher rectus femoris (p = 0.038; d = 0.84) and gluteus medius (p = 0.007; d = 0.54) activities.

INTERPRETATION

This study proved the effectiveness of resistance training using elastic bands on kinetics and muscle activities during walking in male adults with genu valgus disorder. Given that this training regime is low cost, effective, and easy-to-administer, we suggest that it should be implemented as a rehabilitative or preventive means for young adults with genu valgus.

Gait deviations and muscle strength deficits in subjects with patellar instability

BACKGROUND

Abnormal tracking of the patella is a hallmark sign of patellar instability (PI). Gait deviations and strength deficits may exacerbate abnormal tracking. The identification of modifiable gait deviations and strength deficits can aid in developing more effective management strategies for individuals with PI. The purpose of this study was to identify modifiable gait and strength deficits in subjects with PI.

METHODS

32 subjects (16 PI, 16 controls, 3 males/13 females in each group, 21.1 years old, 23.5 BMI), performed an instrumented gait analysis while walking at 1.5 m per second. Subjects' peak hip adduction angles, external rotation angles, hip abduction moments, knee flexion angles, knee adduction angles, and knee extensor moments were measured during walking. Hip abduction, hip external rotation, and knee extension strength were assessed with a handheld dynamometer.

RESULTS

Individuals with PI displayed significantly lower peak knee adduction angles (1.8 ± 2.8° PI, 5.5 ± 4.5° control, p < .01) and peak hip abduction moments (0.2 ± 0.1 Nm/kg*m PI, 0.4 ± 0.1 Nm/kg*m control, p < .01). Subjects with PI were weaker in knee extension strength (14.5 ± 4.1 kg/m PI, 23.8 ± 7.2 kg/m control, p < .01), hip abduction strength (12.1 ± 2.0 kg/m PI, 17.8 ± 4.0 kg/m control, p < .01), and hip external rotation strength (5.5 ± 1.9 kg/m PI, 7.1 ± 1.3 kg/m control, p = .01).

CONCLUSION

Subjects with patellar instability have smaller joint moments and a more valgus knee position while walking. Coupled with deficits in muscle strength, this likely contributes to subjective reports of chronic patellar instability.

LEVEL OF EVIDENCE

III.

The effect of performance demands on lower extremity biomechanics during landing and cutting tasks

BACKGROUND

Anterior cruciate ligament (ACL) injuries commonly occur during the early phase of landing and cutting tasks that involve sudden decelerations. The purpose of this study was to investigate the effects of jump height and jump speed on lower extremity biomechanics during a stop-jump task and the effect of cutting speed on lower extremity biomechanics during a side-cutting task.

METHODS

Thirty-six recreational athletes performed a stop-jump task under 3 conditions: jumping fast, jumping for maximum height, and jumping for 60% of maximum height. Participants also performed a side-cutting task under 2 conditions: cutting at maximum speed and cutting at 60% of maximum speed. Three-dimensional kinematic and kinetic data were collected.

RESULTS

The jumping fast condition resulted in increased peak posterior ground reaction force (PPGRF), knee extension moment at PPGRF, and knee joint stiffness and decreased knee flexion angle compared with the jumping for maximum height condition. The jumping for 60% of maximum height condition resulted in decreased knee flexion angle compared with the jumping for maximum height condition. Participants demonstrated greater PPGRF, knee extension moment at PPGRF, knee valgus angle and varus moment at PPGRF, knee joint stiffness, and knee flexion angle during the cutting at maximum speed condition compared with the cutting at 60% maximum speed condition.

CONCLUSION

Performing jump landing at an increased jump speed resulted in lower extremity movement patterns that have been previously associated with an increase in ACL loading. Cutting speed also affected lower extremity biomechanics. Jump speed and cutting speed need to be considered when designing ACL injury risk screening and injury prevention programs.

The effects of mid-flight whole-body and trunk rotation on landing mechanics: implications for anterior cruciate ligament injuries

The purpose was to quantify the effects of mid-flight whole-body and trunk rotation on knee mechanics in a double-leg landing. Eighteen male and 20 female participants completed a jump-landing-jump task in five conditions: no rotation, testing leg ipsilateral or contralateral (WBRC) to the whole-body rotation direction, and testing leg ipsilateral (TRI) or contralateral to the trunk rotation direction. The WBRC and TRI conditions demonstrated decreased knee flexion and increased knee abduction angles at initial contact (2.6 > Cohen's dz > 0.3) and increased peak vertical ground reaction forces and knee adduction moments during the 100 ms after landing (1.7 > Cohen's dz > 0.3). The TRI condition also showed the greatest knee internal rotation angles at initial contact and peak knee abduction and internal rotation angles and peak knee extension moments during the 100 ms after landing (2.0 > Cohen's dz > 0.5). Whole-body rotation increased contralateral knee loading because of its primary role in decelerating medial-lateral velocities. Trunk rotation resulted in the greatest knee loading for the ipsilateral knee due to weight shifting and mechanical coupling between the trunk and lower extremities. These findings may help understand altered trunk motion in anterior cruciate ligament injuries.

Effects of Corrective Training on Drop Landing Ground Reaction Force Characteristics and Lower Limb Kinematics in Older Adults With Genu Valgus: A Randomized Controlled Trial

The aim of this study was to identify the effects of a corrective exercise program on landing ground reaction force characteristics and lower limb kinematics in older adults with genu valgus. A total of 26 older male adults with genu valgus were randomized into two groups. An experimental group conducted a 14-week corrective exercise program, whereas a control group did not perform any exercise. The experimental group displayed lower peak vertical, peak anterior and posterior, and peak medial ground reaction force components during the posttest compared with the pretest. The vertical loading rate, impulses, and free moment amplitudes were not statistically different between groups. In the experimental group, the peak knee abduction during the posttest was significantly smaller and the peak hip flexion angle was significantly greater than during the pretest. The authors suggest that this corrective exercise program may be a suitable intervention to improve landing ground reaction forces and lower limb kinematics in older male adults with genu valgus.

Lowering minimum eye height to increase peak knee and hip flexion during landing

The purpose was to determine the effect of lowering minimum eye height through an externally focused object on knee and hip flexion and impact forces during jump-landing. Kinematics and ground reaction forces were collected when 20 male and 19 female participants performed jump-landing trials with their natural minimum eye height, and trials focusing on lowering their minimum eye height to an external object, which was set at 5% or 10% of standing height lower. Participants demonstrated decreased minimum eye height and increased peak knee and hip flexion during early-landing and stance phase when focusing on lowering eye height to the external object (p < 0.01). Peak vertical ground reaction forces during early-landing also decreased for the greater force group (p < 0.001). Jump-landing training through manipulating eye height provides a strategy that involves an external focus and intrinsic feedback, which may have advantages in promoting learning and practical application.

Does chronic ankle instability influence lower extremity muscle activation of females during landing?

Much remains unclear about how chronic ankle instability (CAI) could affect knee muscle activations and interact with knee biomechanics. Therefore, the purpose of this study was to assess the influence of CAI on the lower extremity muscle activation at the ankle and knee joints during landings on a tilted surface. A surface electromyography system and two force plates were used to collect lower extremity muscle activation of 21 young female individuals with CAI and 21 pair-matched controls during a double-leg landing with test limb landing on the tilted surface. In the pre-landing phase, compared to controls, CAI participants displayed a reduced ankle evertor activation that could place CAI at a high risk of giving way or sprain injury. In the landing phase, an increased tibialis anterior activation of CAI led to increased co-contraction of ankle muscles in the sagittal and frontal plane. A greater ankle muscle co-contraction could increase the ankle stability during landings but may adversely influence the knee muscle activations (e.g., a greater co-contraction ratio of quadriceps to hamstrings). Relevant training programs (e.g., increasing pre-landing peroneal activation, and optimizing activation ratio of quadriceps to hamstrings) may help individuals with CAI improving ankle stability and reduce atypical knee loading during landings.

Relationship Between Force Production During Isometric Squats and Knee Flexion Angles During Landing

Decreased knee flexion angles during landing are associated with increased anterior cruciate ligament loading. The underlying mechanisms associated with decreased self-selected knee flexion angles during landing are still unclear. The purpose of this study was to establish the relationship between the peak force production at various knee flexion angles (35, 55, 70, and 90°) during isometric squats and the actual knee flexion angles that occur during landing in both men and women. A total of 18 men and 18 women recreational/collegiate athletes performed 4 isometric squats at various knee flexion angles while vertical ground reaction forces were recorded. Participants also performed a jump-landing-jump task while lower extremity kinematics were collected. For women, significant correlations were found between the peak force production at 55 and 70° of knee flexion during isometric squats and the knee flexion angle at initial contact of landing. There were also significant correlations between the peak force production at 55, 70, and 90° of knee flexion during isometric squats and the peak knee flexion angle during landing. These correlations tended to be stronger during isometric squats at greater knee flexion compared with smaller knee flexion. No significant correlations were found for men. Posture-specific strength may play an important role in determining self-selected knee flexion angles during landing for women.

The effect of time-of-day on static and dynamic balance in recreational athletes

The purpose of this study was to investigate the effect of time-of-day (morning vs. afternoon) on static and dynamic balance in recreational athletes. A total of 34 recreational athletes completed the single-leg stance test with or without eyes open, lower quarter Y-balance test, upper quarter Y-balance test, and single-leg landing balance test in a random order in the morning (7:00-10:00 am) and afternoon (3:00-6:00 pm) for two consecutive days. Compared with the morning, participants demonstrated decreased centre of pressure (COP) sway areas (p = 0.002; Cohen's d (d) = 0.28) and sway speeds (p = 0.002; d = 0.17) during the eyes-open single-leg stance test, increased stance time (p = 0.031; d = 0.16) and decreased COP sway areas (p = 0.029; d = 0.22) during the eyes-closed single-leg stance test, and increased reaching distances (p = 0.024; d = 0.10) during the upper quarter Y-balance test in the afternoon. The between-day effect (day 1 vs. day 2) was observed for several parameters. Time-of-day had a minimal effect on dynamic balance and a noticeable effect on static balance. Time-of-day may be considered as a factor in designing balance training programmes and intervention studies for recreational athletes.