Antonio’s Recommended Reading, Research, & Review for Human Performance - Issue #16

XSENSOR's Sports Performance Science Contributor, Antonio Robustelli, MSc, CSCS (Sports Performance Scientist & Technologist with OmniAthlete Performance Concept), offers his take on essential and recommended reading, research, and review for plantar pressure applications using gait analysis for athletes.

Be sure to tune in to get the abstracts, summaries, and key takeaways, or read the complete studies.

Research Title: Muscle Strength & Foot Pressure Vary Depending on the Type of Foot Pain

Authors: Lee J. H., Hwang J., Park H., Kang H., Song W., Choi D. A., Seong C. H., Jang W. Y.

Journal: Scientific Reports

Publication Year: 2024

Abstract

This study compared muscle strength and foot pressure among patients with metatarsalgia, patients with plantar fasciitis, and healthy controls. A total of 31 patients with foot pain (14 metatarsalgia and 17 plantar fasciitis) and 29 healthy controls participated in the study. The strengths of the plantar flexor and hip muscles were measured using isokinetic and handheld dynamometers, respectively. Foot pressure parameters, including the pressure-time integral (PTI) and foot arch index (AI), were assessed using pedobarography. Compared with the healthy control group, plantar flexor strength was significantly reduced in the affected feet of the metatarsalgia and plantar fasciitis groups (F = 0.083, all p < 0.001); however, hip strength was significantly decreased only in the affected feet of the metatarsalgia group (F = 20.900, p < 0.001). Plantar flexor (p < 0.001) and hip (p = 0.004) strength were significantly lower in the metatarsalgia group than in the plantar fasciitis group. The PTI was lower in the forefeet of the affected feet in the metatarsalgia (p < 0.001) and plantar fasciitis (p = 0.004) groups. Foot AI (p < 0.001) was significantly reduced only in the metatarsalgia group. These results suggest the need to consider evaluating muscle strength and foot pressure in both feet for the diagnosis and treatment of foot pain.

Why the Study is Relevant

The study aims to compare muscle strength, foot pressure, and foot posture among patients with metatarsalgia, those with plantar fasciitis, and healthy controls. The authors hypothesize that patients with metatarsalgia and plantar fasciitis will exhibit decreased muscle strength, increased foot pressure, and distinct foot postures compared with healthy controls.

The study employs a prospective, comparative case-control design with a small sample size of 31 patients. The inclusion and exclusion criteria were described correctly; however, the measurement process involved measuring hip muscle strength with patients lying on their side, while measurement in weight-bearing positions would have been more specific in relation to foot pain.

Summary

Foot pain is highly prevalent at various ages and is especially common in middle-aged and older women. It can lead to a variety of musculoskeletal problems and is associated with decreased activities of daily living, impaired balance, and an increased risk of falls. Hence, the diagnosis and management of foot pain are crucial for promoting physical activity and enhancing quality of life.

In middle-aged and older women, the most common causes of foot pain are plantar fasciitis and metatarsalgia.

The authors of this study aimed to investigate whether patients with metatarsalgia and plantar fasciitis would exhibit a decrease in muscle strength and an increase in foot pressure compared to control subjects.

Key Takeaways

• Compared with healthy controls, patients with metatarsalgia and plantar fasciitis exhibited decreased strength in the plantar flexors and hip muscles.

• Foot pressure is low in the forefoot of the affected foot, but high in the rearfoot of the affected and unaffected foot.

Read the full study.

Research Title: Relationships Between Plantar Pressure Distribution & Rearfoot Alignment in the Taiwanese College Athletes with Plantar Fasciopathy During Static Standing & Walking

Authors: Chow T. H., Chen Y. S., Hsu C. C.

Journal: International Journal of Environmental Research & Public Health

Publication Year: 2021

Abstract

Background: Plantar fasciopathy (PF) is usually related to changes in foot arch, foot shape, and rearfoot posture. However, little research has been conducted using large-scale datasets, and even less has focused on the plantar pressure distributions (PPDs) of different genders of PF athletes. This study aimed to investigate the relationships among the arch index (AI), the PPDs, and the rearfoot postural alignment in hundreds of college athletes with PF during static standing and walking.

Methods: A cross-sectional study of 100 male and 102 female athletes with PF was undertaken. The PF athletes' pain assessment and self-reported health status were evaluated to identify their areas of musculoskeletal pain.

Results: The PF athletes' PPDs mainly concentrated on the inner feet in static standing and transferred to the lateral forefeet during the midstance phase of walking. The males' PPDs from the static standing to the midstance phase of walking are mainly assigned to the anterolateral feet. The females' PPDs mostly transferred to the posterolateral aspect of the feet. The PF athletes' static rearfoot alignment matched the valgus posture pattern. The medial band of the plantar fascia and the calcaneus were the common musculoskeletal pain areas.

Conclusions: Characteristics of higher plantar loads beneath medial feet associated with rearfoot valgus in bipedal static stance could be the traceable features for PF-related foot diagrams. Higher plantar loads are primarily exerted on the lateral forefoot during the midstance phase of walking and are specifically concentrated on the outer foot during the transition from a static to a dynamic state. Pain profiles seem to echo PPDs, which could serve as the traceable beginning for the possible link between pronated, low-arched feet, PF, metatarsalgia, calcanitis, and Achilles tendinitis.

Why the Study is Relevant

The study aims to establish the overall reliability of the relationships among the arch index (AI), the plantar pressure distributions (PPDs), and the rearfoot postural alignment by using the large-scale datasets of the college athletes with PF during static standing and walking.

The study has a cross-sectional design and involves a considerable sample size (n = 411) of Taiwanese college athletes.

Summary

Plantar fasciopathy (PF) ranks as the third most common musculoskeletal disorder among runners and is characterised by pain at the insertion of the plantar fascia. The prevailing consensus suggests that the combination of medial longitudinal arch (MLA) height and rearfoot valgus angles is a reliable indicator for predicting pressure-time integrals in the midfoot and rearfoot regions of healthy individuals who run regularly.

The authors of this study tried to ascertain the relationships of the lower extremity musculoskeletal pain caused by PF by examining the correlation between the lower limb pain profiles and plantar pressure distributions.

Key Takeaways

• Higher plantar loads are distributed on the medial part of the foot, accompanied by a rearfoot valgus in bipedal static stance.

• Plantar loads of the athletes with plantar fasciopathy were exerted primarily on the anterolateral part of the foot in males, whilst distributed on the posterolateral part of the foot in females.

Read the full study.

Research Title: The Effect of Foot Orthoses with Forefoot Cushioning or Metatarsal Pad on Forefoot Peak Plantar Pressure in Running

Authors: Hahni M., Hirschmuller A., Baur H.

Journal: Journal of Foot & Ankle Research

Publication Year: 2016

Abstract

Background: Foot orthoses are frequently used in sports for the treatment of overuse complaints, with sufficient evidence available for specific foot-related overuse pathologies like plantar fasciitis, rheumatoid arthritis, and foot pain (e.g., metatarsalgia). One important aim is to reduce plantar pressure under prominent areas, such as the metatarsal heads. For the forefoot region, mainly two common strategies exist: metatarsal pad (MP) and forefoot cushioning (FC). This study aimed to evaluate which of these orthosis concepts is superior in reducing plantar pressure in the forefoot during running.

Methods: Twenty-three (13 female, 10 male) asymptomatic runners participated in this cross-sectional experimental trial. Participants ran in a randomised order under two experimental conditions (MP, FC) and a control condition (C) on a treadmill (2.78 ms-1) for 2 minutes, respectively. Plantar pressure was measured with the in-shoe plantar pressure measurement device pedar-x®-System, and the mean peak pressure averaged from ten steps in the forefoot (primary outcome), and the total foot was analysed. Insole comfort was measured with the Insole Comfort Index (ICI, sum score 0-100) after each running trial. The primary outcome was tested using the Friedman test (α = 0.05). Secondary outcomes were analyzed descriptively (mean ± SD, lower & upper 95% CI, median, and interquartile range (IQR)).

Results: Peak pressure [kPa] in the forefoot was significantly lower wearing FC (281 ± 80, 95%-CI: 246-315) compared to both C (313 ± 69, 95%-CI: 283-343; p = .003) and MP (315 ± 80, 95%-CI: 280-350; p = .001). No significant difference was found between C and MP (p = .858). Peak pressures under the total foot were: C: 364 ± 82, 95% CI: 328-399; MP: 357 ± 80, 95% CI: 326-387; FC: 333 ± 81, 95% CI: 298-368. Median ICI sum scores were: C 50, MP 49, FC 64.

Conclusions: In contrast to the metatarsal pad orthosis, the forefoot cushioning orthosis achieved a significant reduction of peak pressure in the forefoot of recreational runners. Consequently, the use of a prefabricated forefoot cushioning orthosis should be favoured over a prefabricated orthosis with an incorporated metatarsal pad in recreational runners with normal height arches.

Why the Study is Relevant

The study aims to evaluate and compare the effect of forefoot cushioning and a metatarsal pad on peak pressure in the forefoot of asymptomatic recreational runners.

The design is a cross-sectional experimental trial with a low sample size (n = 25).

While the research topic aimed to answer an important question, some limitations are present in the description of the inclusion/exclusion criteria, as well as in the fact that participants were encouraged to run with a rearfoot strike pattern and on a treadmill, which limits the transferability of the results to a real-world scenario.

Summary

Overuse remains a significant contributor to running injuries, although discussion regarding the underlying aetiological factors persists. Several researchers have identified risk factors, including extended weekly training distances, a prior history of injuries, modifications in gait biomechanics, and variations in foot posture. Foot orthoses have been recognized as a potential strategy for reducing the incidence of lower extremity injuries by diminishing both the magnitude and rate of loading. In this study, the authors hypothesized that there would be no significant difference in peak forefoot pressure between interventions using a forefoot cushioning orthosis and those employing a metatarsal pad.

Key Takeaways

• The forefoot cushioning orthosis was able to achieve a significant reduction of peak pressure in the forefoot of recreational runners.

• Prefabricated orthoses with forefoot cushioning reduce peak pressure in the forefoot more than prefabricated orthoses with an incorporated metatarsal pad.

• Cushioning should be considered if pressure reduction is the primary goal for runners with normal-height arches.

Read the full study.