Ankle and Midfoot Power During Single-Limb Heel Rise in Healthy Adults

Midfoot and ankle movement coordination during heel rise is disrupted in people with diabetes and peripheral neuropathy

BACKGROUND

A heel rise task can be used to evaluate midfoot and ankle movement dysfunction in people with diabetes mellitus and peripheral neuropathy. Quantifying movement coordination during heel rise is important to better understand potentially detrimental movement strategies in people with foot pathologies; however, coordination and the impact of limited excursion on coordination is not well-understood in people with diabetes.

METHODS

Sixty patients with diabetes mellitus and peripheral neuropathy, and 22 older and 25 younger controls performed single-limb heel rise task. Midfoot (forefoot relative to hindfoot) sagittal and ankle (hindfoot relative to shank) sagittal and frontal kinematics were measured and normalized to time (0 to 100%). Cross-correlation coefficients were calculated across individuals in each group. A graphical illustration was used to interpret the relationship of midfoot and ankle excursion and cross-correlation coefficient during heel rise.

FINDINGS

People with diabetes mellitus and peripheral neuropathy showed significantly lower midfoot and ankle cross-correlation coefficients during heel rise compared to older controls (p = 0.003-0.007). There was no difference in the midfoot and ankle cross-correlation coefficients during heel rise for the older and younger controls (p = 0.059-0.425). The graphic data illustrated a trend of greater excursion of two joints and a higher cross-correlation coefficient. Some individuals with lower excursion showed a high cross-correlation coefficient.

INTERPRETATION

Foot pathologies, but not aging, impairs midfoot and ankle movement coordination during heel rise task. Investigating both movement coordination as well as joint excursion would better inform and characterize the dynamic movements of midfoot and ankle during heel rise task.

The single-leg heel raise does not predict maximal plantar flexion strength in healthy males and females

Introduction

The single-leg heel raise test (SLHR) is commonly used in clinical settings to approximate plantar flexor strength, yet this is neither validated nor supported physiologically. The purposes of this study were to: determine (1) associations between SLHR repetitions, maximal plantar flexor strength, and reductions in strength; and (2) whether sex differences exist in performance of the SLHR.

Methods

Twenty-eight young, healthy participants (14 males,14 females, 19–30 years) performed repeated single-leg heel raises to task failure. Pre- and post-task measures included maximal voluntary isometric contractions (MVIC), and voluntary activation and contractile properties of the plantar flexor muscles, assessed using peripheral electrical stimulation of the tibial nerve. Surface electromyography was recorded for the medial and lateral gastrocnemius, soleus, and anterior tibialis muscles.

Results

The SLHR resulted in 20.5% reductions in MVIC torque (p<0.001). However, the number of SLHR repetitions was not correlated with either the baseline MVIC (maximal strength; p = 0.979) or the reduction in MVIC following the SLHR (p = 0.23). There were no sex differences in either the number of SLHR repetitions (p = 0.14), baseline MVIC torque (p = 0.198), or the reduction of MVIC (p = 0.14). MVIC decline was positively associated with the reduction in voluntary activation (r = 0.841, p<0.001), but was not associated with the change in twitch amplitude (p = 0.597).

Conclusions

The SLHR was similar in young males and females yet was a poor predictor of maximal plantar flexor strength but evaluates performance fatigability of the lower extremity specific to dynamic contractions. The reduction in maximal strength at task failure was explained by reduced neural drive to the plantar flexor muscles in both males and females.

Impact statement

SLHR performance is not a clinical assessment of plantar flexor strength but assesses dynamic lower extremity fatigability that is similar in males and females. Alternate clinical measures for maximal plantar flexion strength need to be developed.

Heel Rise and Non-Weight-Bearing Ankle Plantar Flexion Tasks to Assess Foot and Ankle Function in People With Diabetes Mellitus and Peripheral Neuropathy

OBJECTIVE

The objective of this study was to examine the effects of diabetes mellitus and peripheral neuropathy (DMPN), limited joint mobility, and weight-bearing on foot and ankle sagittal movements and characterize the foot and ankle position during heel rise.

METHODS

Sixty people with DMPN and 22 controls participated. Primary outcomes were foot (forefoot on hindfoot) and ankle (hindfoot on shank) plantar-flexion/dorsiflexion angle during 3 tasks: unilateral heel rise, bilateral heel rise, and non-weight-bearing ankle plantar flexion. A repeated-measures analysis of variance and Fisher exact test were used.

RESULTS

Main effects of task and group were significant, but not the interaction in both foot and ankle plantar flexion. Foot and ankle plantar flexion were less in people with DMPN compared with controls in all tasks. Both DMPN and control groups had significantly less foot and ankle plantar flexion with greater weight-bearing; however, the linear trend across tasks was similar between groups. The DMPN group had a greater percentage of individuals in foot and/or ankle dorsiflexion at peak unilateral heel rise compared with controls, but the foot and ankle position was similar at peak bilateral heel rise between DMPN and control groups.

CONCLUSION

Foot and ankle plantar flexion is less in people with DMPN. Less plantar flexion in non-weight-bearing suggests that people with DMPN have limited joint mobility. However, peak unilateral and bilateral heel rise is less than the available plantar flexion range of motion measured in non-weight-bearing, indicating that limited joint mobility does not limit heel rise performance. A higher frequency of people with DMPN are in foot and ankle dorsiflexion at peak unilateral heel rise compared with controls, but the position improved with lower weight-bearing.

IMPACT

Proper resistance should be considered with physical therapist interventions utilizing heel rise because foot and ankle plantar flexion position could be improved by reducing the amount of weight-bearing.