Development of a foot and ankle strengthening program for the treatment of plantar heel pain: a Delphi consensus study.

BACKGROUND: People with plantar heel pain (PHP) have reduced foot and ankle muscle function, strength and size, which is frequently treated by muscle strengthening exercises. However, there has been little investigation of what exercises are used and there is no sound evidence base to guide practice. This study aimed to develop a consensus-driven progressive muscle strengthening program for PHP. METHODS: Thirty-eight experts were invited to participate in the study over three rounds. Round 1 was an open-ended questionnaire that provided the core characteristics of progressive strengthening programs designed for three different adult patient types with PHP (younger athletic, overweight middle-aged, older), which were presented as vignettes. In Round 2, experts indicated their agreement to the proposed exercises and training variables. In Round 3, experts were presented with amendments to the exercises based on responses from Round 2 and indicated their agreement to those changes. Consensus was achieved when > 70% of experts agreed. RESULTS: Two experts were ineligible and 12 declined, leaving 24 (67%) who participated in Round 1. Eighteen (75%) completed all three rounds. From Round 1, progressive strengthening programs were developed for the three vignettes, which included 10 different exercises and three training variables (sets / repetitions, weight, and frequency). In Round 2, 68% (n = 17) of exercises and 96% (n = 72) of training variables reached consensus. In Round 3, only exercise changes were presented and 100% of exercises reached consensus. CONCLUSIONS: This study provides three progressive strengthening programs agreed to by experts that can be used in future clinical trials to determine the effectiveness of muscle strengthening for PHP. In addition, clinicians could use the programs as part of a rehabilitation strategy with the caveat that they may change as more research is conducted.

Muscle Function and Muscle Size Differences in People With and Without Plantar Heel Pain: A Systematic Review.

BACKGROUND: Plantar heel pain is a common condition, but little is known about the relationship between muscle strength and plantar heel pain. OBJECTIVES: To review the evidence relating to muscle strength in those with and without plantar heel pain. METHODS: We systematically reviewed the literature by searching key databases. Included studies assessed muscle strength (or endurance or size as proxies) in those with and without plantar heel pain. A modified Downs-Black quality index was used to assess study quality and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool was used to evaluate the strength of the evidence. Meta-analysis was performed where possible. RESULTS: Seven studies met the eligibility criteria. Hallux plantar flexion, lesser toe plantar flexion, ankle dorsiflexion, ankle inversion, and ankle eversion strength values were reduced in those with heel pain compared to those without; however, there was inconsistency in the findings between studies. No difference was found in calf muscle endurance between those with and without plantar heel pain (standardized mean difference, 0.01; 95% confidence interval: -0.56, 0.59). Generally, foot muscle volume was smaller in people with plantar heel pain compared to those without. The quality of individual studies was generally high (score range, 11-16/17 on the modified Downs-Black quality index); however, the GRADE ratings suggest the strength of this evidence to be very low. CONCLUSION: People with plantar heel pain have reduced strength and volume of the foot muscles, but there is no discernible difference in calf muscle endurance. These findings should be interpreted with respect to the very low GRADE ratings and are likely to change with further research. Accordingly, the role of muscle strength in plantar heel pain is worthy of further investigation. J Orthop Sports Phys Ther 2019;49(12):925-933. Epub 9 Oct 2019. doi:10.2519/jospt.2019.8588.