The associations of leg lean mass with foot pain, posture and function in the Framingham foot study

Intrinsic foot muscle size and associations with strength, pain and foot-related disability in people with midfoot osteoarthritis

BACKGROUND

To compare intrinsic foot muscle size between people with and without symptomatic midfoot osteoarthritis, and examine the association between muscle size and strength, pain and foot-related disability.

METHODS

Twenty-three participants with symptomatic midfoot osteoarthritis and 23 age, sex and BMI matched controls were included. Intrinsic foot muscle cross-sectional area was measured using MRI. Hand-held dynamometry was used to assess foot and ankle muscle strength, and foot-related pain and disability was measured using Manchester Foot Pain & Disability Index.

FINDINGS

Small and non-statistically significant differences were found in intrinsic foot muscle cross-sectional area between the two groups (effect sizes 0.15-0.26, p > 0.05). Muscle strength was reduced in the midfoot osteoarthritis group, with differences of 12-33% (effect sizes 0.47-1.2). In the control group, moderate positive associations) existed between foot muscle cross-sectional area and lesser digits flexor strength (r = 0.5 to 0.7, p < 0.05). Conversely, in the midfoot osteoarthritis group, negligible positive associations were found (r < 0.3, p > 0.05). Associations between foot muscle cross-sectional with and pain and disability scores in the midfoot osteoarthritis group were negligible (r < -0.3, p > 0.05).

INTERPRETATION

Despite reductions in maximal isometric muscle strength, midfoot osteoarthritis does not appear to be associated with reduced intrinsic foot muscle cross-sectional area measured by MRI. Muscle compositional or neural factors may explain the reductions in muscle strength and variation in symptoms in people with midfoot osteoarthritis and should be investigated.

ISB recommendations for skin-marker-based multi-segment foot kinematics

The foot is anatomically and functionally complex, and thus an accurate description of intrinsic kinematics for clinical or sports applications requires multiple segments. This has led to the development of many multi-segment foot models for both kinematic and kinetic analyses. These models differ in the number of segments analyzed, bony landmarks identified, required marker set, defined anatomical axes and frames, the convention used to calculate joint rotations and the determination of neutral positions or other offsets from neutral. Many of these models lack validation. The terminology used is inconsistent and frequently confusing. Biomechanical and clinical studies using these models should use established references and describe how results are obtained and reported. The International Society of Biomechanics has previously published proposals for standards regarding kinematic and kinetic measurements in biomechanical research, and in this paper also addresses multi-segment foot kinematics modeling. The scope of this work is not to prescribe a particular set of standard definitions to be used in all applications, but rather to recommend a set of standards for collecting, calculating and reporting relevant data. The present paper includes recommendations for the overall modeling and grouping of the foot bones, for defining landmarks and other anatomical references, for addressing the many experimental issues in motion data collection, for analysing and reporting relevant results and finally for designing clinical and biomechanical studies in large populations by selecting the most suitable protocol for the specific application. These recommendations should also be applied when writing manuscripts and abstracts.

Preliminary Feasibility Study to Measure the Immediate Changes of Bilateral Asymmetry After Lumbar Spinal Manipulative Therapy in Asymptomatic Athletes

Objective

The purpose of this preliminary study was to assess the feasibility of a study to measure the immediate changes in bilateral asymmetry on physical performance tests before and after lumbar spinal manipulative therapy (SMT).

Methods

Thirteen asymptomatic athletes participated in this study. Each participant underwent a clinical and physical evaluation for inclusion according to eligibility criteria. Assessments were performed in all participants and included a physical test symmetry sequence (static standing position, squat, and countermovement jump) before and after lumbar SMT intervention. The immediate changes were quantitatively measured from before to after intervention by statistical calculations.

Results

All recruited participants completed the study, and none of them reported complaints during participation. Statistically significant differences between before and after lumbar SMT were found only for static symmetry (respectively, mean = 14.4% and 3.7%), not for squatting or the countermovement jump.

Conclusion

According our sample characteristics, asymptomatic athlete participants, presented initially bilateral asymmetry values, such as described in the literature, and after lumbar SMT, these values decreased significantly in static posture. This preliminary study demonstrates the feasibility to measure the pre-to-post changes in symmetry after lumbar SMT intervention. The results showed a great decrease in bilateral symmetry on static symmetry percentage, but none in dynamic tests, which deserves further investigation. Nevertheless, this preliminary study demonstrated the feasibility of measuring the immediate changes in symmetry produced by lumbar SMT, and of a larger study to measure whether lumbar SMT changes symmetry.

Body Fat and Muscle Mass in Association with Foot Structure in Adolescents: A Cross-Sectional Study

Prior studies have investigated associations between body mass index (BMI) and foot structure; however, these studies are limited only to the evaluation of the longitudinal arch of the foot and do not evaluate associations with body composition. Therefore, this study examined associations between body fat percentage (BFP) and muscle mass percentage with foot structure in adolescents. This study was conducted with 158 healthy subjects aged from 11 to 13 years. Body fat percentage and muscle mass percentage were estimated using bioelectrical impedance analysis. A podoscope was used to calculate Clarke's angle (CL), the Wejsflog index (WI), hallux valgus angle (ALPHA), and the angle of the varus deformity of the fifth toe (BETA). Lower values of CL were found in participants with excessive BFP (p = 0.021). No differences were observed in the values of the Wejsflog, ALFA or BETA indices between normal and excessive BFP groups. Participants with the lowest muscle mass percentage were significantly more likely to have lower values of CL and WI (p = 0.014 and p < 0.001, respectively). Excess BFP appeared to have a significant effect on the longitudinal arch and low muscle mass percentage on the longitudinal and transverse arches of the foot in adolescents. There was no association between fat and muscle content with positions of the big and fifth toes.

Leg Muscle Mass and Foot Symptoms, Structure, and Function: The Johnston County Osteoarthritis Project

BACKGROUND

Loss of muscle mass occurs with aging and in lower limbs it may be accelerated by foot problems. In this cross-sectional analysis, we evaluated the relationship of leg muscle mass to foot symptoms (presence or absence of pain, aching, or stiffness), structure while standing (high arch or low arch), and function while walking (pronated or supinated) in a community-based study of Caucasian and African American men and women who were 50-95 years old.

METHODS

In the Johnston County Osteoarthritis Project, leg muscle mass was measured with whole body dual-energy x-ray absorptiometry, and plantar foot pressure data, using predetermined values, were used to classify foot structure and function. Sex-specific crude and adjusted (age, body mass index, and race) linear regression models examined associations of leg muscle mass index (Leg muscle mass [kg]/Height [m](2)) with foot symptoms, structure, and function.

RESULTS

Complete data were available for 1,037 participants (mean age 68 years, mean body mass index 31 kg/m(2), 68% women, 29% African American). In women, pronated foot function was associated with lower leg muscle mass in crude (p = .02), but not adjusted (p = .22), models. A low arch was associated with a higher leg muscle mass in adjusted models for both men and women (p < .01).

CONCLUSIONS

Leg muscle mass was associated with foot structure in our biracial sample, whereas relations between leg muscle mass and foot function were attenuated by age, body mass index, and race. Future longitudinal analyses are needed to explain the temporal relationship between these conditions and how they relate to other aspects of impairment and physical function.