Reductions in rearfoot eversion posture due to proximal muscle strengthening are dependent on foot-ankle varus alignment

BACKGROUND

Strengthening the hip and trunk muscles may decrease foot pronation in upright standing due to expected increases in hip passive torque and lower-limb external rotation. However, considering the increased pronation caused by a more varus foot-ankle alignment, subjects with more varus may experience smaller or no postural changes after strengthening.

OBJECTIVE

To investigate the effects of hip and trunk muscle strengthening on lower-limb posture during upright standing and hip passive torque of women with more and less varus alignment.

METHODS

This nonrandomized controlled experimental study included 50 young, able-bodied women. The intervention group (n = 25) performed hip and trunk muscle strengthening exercises, and the control group (n = 25) maintained their usual activities. Each group was split into two subgroups: those with more and less varus alignment. Hip, shank, and rearfoot-ankle posture and hip passive external rotation torque were evaluated. Mixed analyses of variance and preplanned contrasts were used to assess prepost changes and between-group differences (α = 0.05).

RESULTS

The less-varus subgroup of the intervention group had a reduced rearfoot eversion posture (P = 0.02). No significant changes were observed in the less-varus subgroup of the control group (P = 0.31). There were no significant differences in posture between the control and intervention groups when varus was not considered (P ≥ 0.06). The intervention group had increased hip passive torque (P = 0.001) compared to the control group, independent of varus alignment.

CONCLUSION

Despite the increases in hip passive torque, the rearfoot eversion posture was reduced only in women with a less-varus alignment. Having more foot-ankle varus may prevent eversion reductions.

Can Clinicians Trust Objective Measures of Hip Muscle Strength From Portable Dynamometers? A Systematic Review With Meta-analysis and Evidence Gap Map of 107 Studies of Reliability and Criterion Validity Using the COSMIN Methodology

OBJECTIVE: To summarize the evidence on reliability and criterion validity of hip muscle strength testing using portable dynamometers. DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: Five databases were searched from inception to March 2023. STUDY SELECTION CRITERIA: We included studies investigating reliability or criterion validity of hip flexor, extensor, abductor, adductor, or internal/external rotator strength testing with portable dynamometers in injury-free individuals or those with pelvic/lower limb musculoskeletal disorders. DATA SYNTHESIS: We performed meta-analyses for each muscle group, position, and method of fixation. We rated pooled results as sufficient (>75% of studies with correlations ≥0.70), insufficient (>75% of studies with correlations <0.70), or inconsistent (sufficient/insufficient results). We assessed the quality of evidence, created evidence gap maps, and made clinical recommendations. RESULTS: We included a total of 107 studies (reliability 103, validity 14). The intrarater and interrater reliability for hip muscle strength testing across different positions and methods of fixation was sufficient (intraclass correlation coefficient = 0.78-0.96) with low- to high-quality evidence. Criterion validity was less investigated and mostly inconsistent (very low-to moderate-quality evidence) with a wide range of correlations (r = 0.40-0.93). CONCLUSION: Hip muscle strength testing using portable dynamometers is reliable. The use of portable dynamometers as clinical surrogates for measuring strength using an isokinetic dynamometer requires further investigation. Clinicians testing hip muscle strength with portable dynamometers should use external fixation seated for hip flexors, prone or supine for hip extensors, side-lying or supine for abductors and adductors, and prone and seated for internal and external rotators. J Orthop Sports Phys Ther 2023;53(11):655-672. Epub 3 October 2023. doi:10.2519/jospt.2023.12045.

Overhead squat assessment reflects treadmill running kinematics

PURPOSE

Overhead squat assessment (OHSA) is a pre-activity dynamic movement analysis tool used to define deviations from an ideal motion pattern which known as compensation. Compensatory movements may result from abnormality in myofascial activity, length-tension relationships, neuro-motor control strategies, osteokinematics and arthrokinematics. The aim of this study is to identify the association between selected biomechanical variables of the ankle, knee, hip, pelvis, torso during OHSA and 16 km/h treadmill running tasks.

METHODS

Thirteen national long distance male runners (17.3 ± 0.5 age (years); 5.89 ± 1.95 experience (years), 57.9 ± 3.7 body mass (kg); 175.4 ± 5.7 height (cm)) participated in this 2controlled laboratory study. Three-dimensional kinematics were collected at 250 Hz using a 9-camera Qualisys motion analysis system (Qualisys AB, Goteborg, Sweden) while participants performed 16 km/h treadmill running and OHSA tasks.

RESULTS

Correlation coefficients demonstrated that OHSA pelvic anterior tilt angle was in a positive association with foot strike (FS), mid-stance (MS), and toe-off (TO) pelvic anterior tilt angles and MS tibial internal rotation on talus, MS ankle pronation, MS hip internal rotation. OHSA pelvic anterior tilt angle was in a negative association with TO hip extension. OHSA maximal hip adduction was positively correlated with MS and stance maximal knee adduction. FS, MS, stance maximal angular dorsiflexion values were positively correlated with OHSA dorsiflexion. Increased OHSA dorsiflexion angle was negatively associated with TO plantar flexion. OHSA pronation was positively associated with MS and stance pronation. MS hip internal rotation, MS hip adduction angles were increased, and MS ankle dorsiflexion was significantly decreased with the increase of trunk forward lean relative to tibia during OHSA.

CONCLUSIONS

OHSA was associated with some important and dysfunction-related hip, knee and ankle kinematics. Running coaches, may use OHSA as an assessment tool before the corrective training plan to detect injury-related compensation patterns to reduce the risk of injury and improve running technique.

Effects of short foot exercise combined with lower extremity training on dynamic foot function in individuals with flexible flatfoot: A randomized controlled trial

BACKGROUND

Flexible flatfoot has demonstrated biomechanical linkages between distal and proximal lower extremities. However, supporting evidence is required to investigate the benefits of short foot exercise (SF) and short foot exercise in combination with lower extremity training (SFLE) on dynamic foot function.

RESEARCH QUESTION

This study aimed to determine the effects of a 6-week SF, 6-week SFLE, or control condition (no intervention) on dynamic foot function during gait in individuals with flexible flatfoot.

METHODS

Forty-five individuals with flexible flatfoot were randomly assigned into three conditions: (1) SF, (2) SFLE, and (3) control conditions. Participants in two intervention programs performed daily training via telerehabilitation and a home-based exercise program. Foot kinematics and center of pressure excursion index (CPEI) during the gait, intrinsic foot muscle test, and navicular drop test were assessed at baseline and after the 6-week intervention program.

RESULTS

Post-intervention participants in the SF and SFLE conditions showed a shorter time to the lowest medial longitudinal arch (MLA) and improved MLA motion during the stance phase compared with the baseline. In addition, participants in the SFLE conditions showed greater changes in CPEI than in the SF and control conditions. Improvements in intrinsic foot muscle and navicular drop tests were also observed in participants in both intervention programs post-intervention.

SIGNIFICANCE

A major finding of the study was the improvement in dynamic foot function during gait in individuals with flexible flatfoot after the six weeks of the SF and SFLE intervention programs. Both intervention programs appear to have the potential for inclusion in a corrective program for individuals with flexible flatfoot.

Relationship between the knee valgus moment and the hip abductor and adductor activity during single-leg landing

OBJECTIVES

To reveal the relationship between the knee valgus moment (KVM) and the hip abductor and adductor activity during single-leg landing.

DESIGN

A cross-sectional study.

SETTING

Laboratory-based, between April 2020 and May 2021.

PARTICIPANTS

Thirty female collegiate athletes.

MAIN OUTCOME MEASURES

KVM, hip adduction angle, hip internal rotation angle, knee valgus angle (KVA), gluteus medius muscle activity, adductor longus muscle activity, adductor longus to gluteus medius activity ratio (ADD/GMED), and vertical component of the ground reaction force (vGRF).

RESULTS

Stepwise multiple regression analysis was performed. KVM was significantly positively associated with KVA (β = 0.613, p < 0.001), vGRF (β = 0.367, p = 0.010), and ADD/GMED (β = 0.289, p = 0.038).

CONCLUSIONS

Increased KVA, vGRF, and ADD/GMED were the independent factors that contributed to increased KVM during single-leg landing, and only ADD/GMED was found among the muscle activity values. The relative muscle activity of the gluteus medius and adductor longus, rather than those of the gluteus medius or adductor longus alone, may be useful in preventing anterior cruciate ligament injury during single-leg landing.

Do posted foot orthoses alter hip biomechanics and pain during walking in women with greater trochanteric pain syndrome?

BACKGROUND

Greater trochanteric pain syndrome (GTPS), including gluteal tendinopathy and bursitis, is a common, painful and debilitating condition. It is thought to involve overload of the gluteal tendons, which may be amplified through increased hip adduction moment (HAM) seen during gait in these individuals. Reducing the aberrant HAM may improve pain and function in this population. We aimed to determine if medially-posted foot orthoses immediately reduce HAM and pain in females with GTPS during walking gait.

METHODS

A double-blind, repeated-measures trial with randomised intervention order compared three conditions in 53 women with GTPS. Participants acted as their own control during baseline (everyday-shoe insole), medially-posted (active) orthosis, or flat insert (sham orthosis) walking. Data were collected via three-dimensional gait analysis for HAM, hip, pelvic, and thorax kinematics; as well as ground reaction force; and pain via the numerical rating scale. Subgroup analysis was performed based on a pronated foot-posture defined by the Foot Posture Index.

RESULTS

A small pain reduction was found between the active orthosis and flat insert (mean difference = -0.444, p = 0.017). No difference was detected for pain between other condition comparisons. Thoracic lateral flexion increased at second-peak HAM between the baseline and active conditions (mean difference = -0.917, p = 0.040). No differences were detected for HAM, remaining kinematic or kinetic variables, or ground reaction force data across the three conditions. No significant differences were detected between any of the three conditions for biomechanical or pain data in the pronated-foot subgroup.

SIGNIFICANCE

A medially-posted foot orthosis did not immediately alter gait biomechanics or provide a clinically meaningful pain reduction in women with GTPS. There is uncertainty regarding the clinical benefit of orthoses in the management of GTPS. Longer-term follow-up or the use of customised orthoses may produce different outcomes and should be explored in future research.

Fatigue of hip abductor muscles implies neuromuscular and kinematic adaptations of the ankle during dynamic balance

OBJECTIVE

Determine whether hip abductor muscle fatigue influenced ankle kinematic and muscle activity during ankle-destabilized tasks.

DESIGN

Cross-sectional study.

METHODS

Twenty-six healthy, active participants performed two tests (Star Excursion Balance Test, SEBT; Weight Bearing Inversion Test, WBIT) for assessment of dynamic balance and ability to control inversion. Participants were equipped with an ankle-destabilizing sandal in inversion and eversion to perform both tests, which were completed before and after a fatiguing exercise of hip abductor muscles (up to 50% reduction in strength). Electromyographic activity of peroneus longus (PL) and brevis (PB), tibialis anterior, gastrocnemius lateralis (GastL) and gluteus medius (GlutM) muscles were recorded. In addition, ankle kinematics were recorded using an inertial measurement unit.

RESULTS

Hip abductor fatigue induced a significant decrease in SEBT scores in three directions (p < 0.01). During SEBT, ankle supination decreased by 3.2° in the anterior and posteromedial directions (p < 0.01). Muscle activity of GastL increased during achievement of three directions (p < 0.05) in response to hip abductor fatigue. In posteromedial direction, PL (p < 0.001) and GlutM (p < 0.01) activity increased with fatigue. During WBIT, inversion angular velocity was not impacted by fatigue while, PB and GastL activity increased after fatiguing exercise (p < 0.005).

CONCLUSION

A decrease in SEBT performance and EMG adaptations with proximal fatigue attest to the importance of the hip abductor muscle in dynamic postural control. This could have important implications in building injury prevention programs. Changes in ankle supination may reflect a protective strategy of the joint in response to hip fatigue.

Effects of Foot-Core Training on Foot-Ankle Kinematics and Running Kinetics in Runners: Secondary Outcomes From a Randomized Controlled Trial

This study investigated the effectiveness of an 8-week foot-core exercise training program on foot-ankle kinematics during running and also on running kinetics (impact loads), with particular interest in biomechanical outcomes considered risk factors for running-related injuries in recreational runners. A single-blind, randomized, controlled trial was conducted with 87 recreational runners randomly allocated to either the control (CG) or intervention (IG) group and assessed at baseline and after 8 weeks. The IG underwent foot-core training 3 times/week, while the CG followed a placebo lower-limb stretching protocol. The participants ran on a force-instrumented treadmill at a self-selected speed while foot-segment motion was captured simultaneously with kinetic measurements. After the intervention, there were statistically significant changed in foot biomechanics, such as: IG participants strike the ground with a more inverted calcaneus and a less dorsiflexed midfoot than those in the CG; at midstance, ran with a less plantarflexed and more adducted forefoot and a more abducted hallux; and at push-off, ran with a less dorsiflexed midfoot and a less adducted and more dorsiflexed hallux. The IG runners also had significantly decreased medial longitudinal arch excursion (p = 0.024) and increased rearfoot inversion (p = 0.037). The 8-week foot-core exercise program had no effect on impact (p = 0.129) and breaking forces (p = 0.934) or on vertical loading rate (p = 0.537), but it was positively effective in changing foot-ankle kinematic patterns.”

Iliopsoas muscle thickness and pelvic alignment in pronated and normal foot postures

It is hypothesized that the subtalar hyperpronation may provoke the development of a biomechanical chain of events in lower extremity alignment. Several studies have shown that pelvic alignment may alter in the presence of immediate foot hyperpronation induced by external forces. It is unknown whether these alterations are presented in chronic foot hyperpronation or not. It is also unknown if these potential postural changes could affect iliopsoas muscle size. Therefore, it appears necessary to carry out thorough research in this study. Twenty nine females with pronated foot posture and twenty seven females with normal foot posture participated in this study. The iliopsoas muscle was measured using ultrasound imaging (USI). Pelvic angle (PA) was measured using reflective markers and digital photography. Intrarater reliability of USI for the iliopsoas muscle thickness was also measured. The results indicated that the iliopsoas muscle thickness and the PA were not different in individuals with pronated foot compared to the normal foot group. However, a good intrarater reliability of USI was found for measuring the iliopsoas muscle thickness.

The effects of foot position on lower extremity kinematics during single leg squat among adolescent male athletes

Objectives

The purpose of this study was to investigate the effect of transverse plane foot position on lower limb kinematics during a single leg squat.

Methods

This was a cross-sectional study conducted among highly-trained male athletes. Only participants who showed normal knee valgus during a drop landing screening test were recruited. Twelve junior athletes performed single leg squats while maintaining a knee flexion angle of 60°. The squats were executed in three foot positions: neutral (0°), adduction (−10°), and abduction (+10°). Three-dimensional motion analysis was used to capture the lower extremity kinematics of the participants’ preferred limb. The hip and knee kinematics in the sagittal, frontal, and transverse planes during squatting were compared across the three foot positions using one-way ANOVA.

Results

The participants showed a normal range of dynamic knee valgus (5.3°±1.6). No statistically significant differences were observed in hip flexion (p = 0.322), adduction (p = 0.834), or internal rotation (p = 0.967) across different foot positions. Similarly, no statistically significant differences were observed in knee flexion (p = 0.489), adduction (p = 0.822), or internal rotation (p = 0.971) across different foot positions.

Conclusion

Small changes in transverse plane foot position do not affect lower extremity kinematics during single leg squat in highly trained adolescent males with normal dynamic knee valgus. Our findings may provide guidance on safer techniques for landing, pivoting, and cutting during training and game situations.

Ultrasound evaluation of the quadriceps muscles in pronated foot posture

OBJECTIVE

The main goal of this study was to investigate the size of all portions of the quadriceps muscles in individuals with pronated foot posture compared to normal foot posture using ultrasound imaging.

DESIGN

Twenty nine females with pronated foot posture and 29 age-, body weight-, body height-matched females with normal foot posture were recruited from university communities. The muscle thicknesses of the rectus femoris (RF), vastus medialis (VM), vastus medialis oblique (VMO), vastus lateralis (VL) and vastus intermedius (VI) were measured using ultrasound imaging.

RESULTS

The thicknesses of the RF and VMO were significantly smaller in individuals with pronated foot posture compared to normal foot posture (p<0.05). No significant differences were observed in the VM, VL, and VI muscle thicknesses in both groups.

CONCLUSION

Based on the results of the present study, it seems that besides the foot and lower leg muscles, an integrated assessment of proximal knee muscles, especially quadriceps, is required in individuals with pronated foot posture.

Reliability of digital photography for assessing lower extremity alignment in individuals with flatfeet and normal feet types

AIM

The aim of this study was to investigate the intratester reliability of digital photographic method for quantifying static lower extremity alignment in individuals with flatfeet and normal feet types.

METHODS

Thirteen females with flexible flatfeet and nine females with normal feet types were recruited from university communities. Reflective markers were attached over the participant's body landmarks. Frontal and sagittal plane photographs were taken while the participants were in a standardized standing position. The markers were removed and after 30 min the same procedure was repeated. Pelvic angle, quadriceps angle, tibiofemoral angle, genu recurvatum, femur length and tibia length were measured from photographs using the Image j software.

RESULTS

All measured variables demonstrated good to excellent intratester reliability using digital photography in both flatfeet (ICC: 0.79-0.93) and normal feet type (ICC: 0.84-0.97) groups.

CONCLUSION

The findings of the current study indicate that digital photography is a highly reliable method of measurement for assessing lower extremity alignment in both flatfeet and normal feet type groups.

Comparison of two incremental protocols for evaluation of hip extension

Abstract Introduction: The hip muscles play an important role in controlling the transverse and frontal plane of the femur during displacement. The hip extension and abduction/adduction exercises are among the most widely evaluated protocols both clinically and in research. Objective: To compare which assessment protocol in an isokinetic strength regime (distal grip-ankle vs. proximal grip-knee) best represents the action of hip extension and to analyze the test-retest reliability in the variables peak force (PF) and work (W). Methods: A total of 20 subjects participated in this research. All participants were female. The mean and standard deviations of age, weight and height were 21 ± 3.9 years, 65 ± 11 kg, 166 ± 3.4 cm, respectively. Results: Significant differences were found in both variables (PF and W) between protocols 1 and 2 (p < 0.05) on assessment days 1 and 2. No differences between days 1 and day 2 in either protocol (p < 0.05) were found. Index values of interclass correlation (ICC) of protocol 1 ranged between 0.38 and 0.86. In protocol 2 the ICC range was between 0.33 and 0.87. Conclusions: In light of these results, the hip extension exercise with a proximal grip best represents the strength of the muscle groups involved in this action.

The effects of isolated ankle strengthening and functional balance training on strength, running mechanics, postural control and injury prevention in novice runners: design of a randomized controlled trial

BACKGROUND

Risk factors have been proposed for running injuries including (a) reduced muscular strength, (b) excessive joint movements and (c) excessive joint moments in the frontal and transverse planes. To date, many running injury prevention programs have focused on a "top down" approach to strengthen the hip musculature in the attempt to reduce movements and moments at the hip, knee, and/or ankle joints. However, running mechanics did not change when hip muscle strength increased. It could be speculated that emphasis should be placed on increasing the strength of the ankle joint for a "ground up" approach. Strengthening of the large and small muscles crossing the ankle joint is assumed to change the force distribution for these muscles and to increase the use of smaller muscles. This would be associated with a reduction of joint and insertion forces, which could have a beneficial effect on injury prevention. However, training of the ankle joint as an injury prevention strategy has not been studied. Ankle strengthening techniques include isolated strengthening or movement-related strengthening such as functional balance training. There is little knowledge about the efficacy of such training programs on strength alteration, gait or injury reduction.

METHODS/DESIGN

Novice runners will be randomly assigned to one of three groups: an isolated ankle strengthening group (strength, n = 40), a functional balance training group (balance, n = 40) or an activity-matched control group (control, n = 40). Isokinetic strength will be measured using a Biodex System 3 dynamometer. Running kinematics and kinetics will be assessed using 3D motion analysis and a force platform. Postural control will be assessed by quantifying the magnitude and temporal structure of the center of pressure trace during single leg stance on a force platform. The change pre- and post-training in isokinetic strength, running mechanics, and postural control variables will be compared following the interventions. Injuries rates will be compared between groups over 6 months.

DISCUSSION

Avoiding injury will allow individuals to enjoy the benefits of participating in aerobic activities and reduce the healthcare costs associated with running injuries.

TRIAL REGISTRATION

Current Controlled Trial NCT01900262.

Successful rehabilitation of a recreational endurance runner: initial validation for the Bunkie test

This case report details the musculoskeletal evaluation and the successful rehabilitation of a 24-year-old female recreational distance runner who self-referred to physical therapy with an acute bout of low back pain (LBP). Her LBP was provoked during each distance run. The patient's musculoskeletal evaluation revealed core weakness, especially on the left. A recently reported functional test, the Bunkie test, was administered as part of the physical evaluation. The scores from the Bunkie test correlated with other quantitative and qualitative findings. A therapeutic exercise program emphasizing core stabilization was prescribed. The patient was able to shortly return to running pain-free.

The reliability of portable fixed dynamometry during hip and knee strength assessments

CONTEXT

Insufficient lower extremity strength may be a risk factor for lower extremity injuries such as noncontact anterior cruciate ligament tears. Therefore, clinicians need reliable instruments to assess strength deficiencies.

OBJECTIVE

To assess the intrarater, interrater, intrasession, and intersession reliability of a portable fixed dynamometer in measuring the strength of the hip and knee musculature.

DESIGN

Crossover study.

SETTING

Sports medicine research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Three raters (A, B, C) participated in this 2-phase study. Raters A and B tested 11 healthy college graduate students (2 men, 9 women) in phase 1. Raters A and C tested 26 healthy college undergraduate students (7 men, 19 women) in phase 2.

MAIN OUTCOME MEASURE(S)

The dependent variables for the study were hip adductor, hip abductor, hip flexor, hip extensor, hip internal rotator, hip external rotator, knee flexor, and knee extensor peak force.

RESULTS

The phase 1 intrasession intraclass correlation coefficients for sessions 1, 2, and 3 ranged from 0.88 to 0.99 (SEM = 0.08-3.02 N), 0.85 to 0.99 (SEM = 0.26-3.88 N), and 0.92 to 0.96 (SEM = 0.52-2.76 N), respectively. Intraclass correlation coefficients ranged from 0.57 to 0.95 (SEM = 1.72-13.15 N) for phase 1 intersession values, 0.70 to 0.94 (SEM = 1.42-9.20 N) for phase 2 intrarater reliability values, and 0.69 to 0.88 (SEM = 1.20-8.50 N) for phase 2 interrater values.

CONCLUSIONS

The portable fixed dynamometer showed good to high intrasession and intersession reliability values for hip and knee strength. Intrarater and interrater reliability were fair to high, except for hip internal rotation, which showed poor reliability.