Antonio’s Recommended Reading, Research, & Review for Human Performance - Issue #10 | April 2024

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: Injury of Flexor Hallucis Longus Tendon in Amateur Marathon Runners Results in Abnormal Plantar Pressure Distribution: Observational Study

Authors: Chen J, Zhang P, Hou I, Bao H, Li J, Zhao J.

Journal: BMC Musculoskeletal Disorders

Publication Year: 2024

Abstract

Objective: To analyze the changes in plantar pressure in amateur marathon runners with flexor halluics longus (FHL) tendon injury using the Medtrack-Gait plantar pressure measurement system and to explore whether the plantar pressure data can be used as an index for the diagnosis of injury.

Methods: 39 healthy amateur marathon runners without any ankle joint symptoms were recruited. Dynamic and static plantar pressure data were measured using the Medtrack-Gait pressure plate. According to MRI imaging findings, whether the FHL tendon was injured or not was judged, and the dynamic and static data were divided into the injury group and control group. The data with statistically significant differences between the two groups were used to make the receiver operating characteristic (ROC) curve.

Results: The maximum contact area (PA) of the first metatarsal (M1) region, the maximum load-bearing peak value (PW), and the time pressure integral (PMPTI) of the second metatarsal (M2) region in the injury group were lower than those in the control group, respectively (P < 0.05). The PA of the fifth metatarsal (M5) region was higher than that in the control group (P < 0.05). The area under curve (AUC) value of the ROC curve of the PA of the M1 region, the PW, and the PMPTI of the M2 region were statistically significant (P < 0.05).

Conclusion: FHL tendon injury resulted in decreased PA in M1, decreased PW and PMPTI in M2, and increased PA in the M5 region, suggesting that it resulted in a force shift from the medial to the lateral side of the foot. The PA of M1, PW, and PMPTI of M2 have certain diagnostic values for early FHL injury in amateur marathon runners.

Why the Study is Relevant

The study aims to investigate whether the alteration of plantar pressure distribution in amateur marathon runners can be used to indicate the potential risk of injuries related to running.

The study design has an acceptable minimum sample size of 39 subjects. However, the testing protocol seems to be missing a few descriptive elements. There is no mention of whether the test is performed barefoot or with shoes, which affects how the testing outcome translates to the real-world environment of marathon running.

Furthermore, it's a cross-sectional study, so it is indicative of a single point in time, without considering that no information on the runners' training status prior to testing is provided.

Summary

Marathon running is a long-distance sport that challenges the limits of endurance; thus, musculoskeletal injuries of the lower limbs are very common.

The ankle joint is one of the most injured sites among marathon runners, and injuries to the FHL tendon may occur due to excessive plantarflexion of the ankle joint caused by repetitive push-off during prolonged running.

The authors of this study investigated whether gait analysis with plantar pressure mapping may assist in the early detection of FHL tendon injury.

Key Takeaways

• It's possible that FHL tendon injury causes a transfer of force from the medial to the lateral side of the foot.
• Plantar pressure may serve as an alternative method for early detection of FHL tendon injury.

Read the full study.

Research Title: The Influence of General and Local Muscle Fatigue on Kinematics and Plantar Pressure Distribution During Running: A Systematic Review and Meta-Analysis

Authors: Aly Hazzaa W, Hottenrott L, Kamal MA, Mattes K.

Journal: Sports (Basel)

Publication Year: 2023

Abstract

Fatigue has the potential to alter how impact forces are absorbed during running, heightening the risk of injury. Conflicting findings exist regarding alterations in both kinematics and plantar pressure. Thus, this systematic review and subsequent meta-analysis were conducted to investigate the impact of general and localized muscle fatigue on kinematics and plantar pressure distribution during running. Initial searches were executed on 30 November 2021 and updated on 29 April 2023, encompassing PubMed, The Cochrane Library, SPORTDiscus, and Web of Science without imposing any restrictions on publication dates or employing additional filters. Our PECOS criteria included cross-sectional studies on healthy adults during their treadmill running to mainly evaluate local muscle fatigue, plantar pressure distribution, biomechanics of running (kinematics, kinetics, and EMG results), and temporospatial parameters. The literature search identified 6,626 records, with 4,626 studies removed for titles and abstract screening. 201 articles were selected for full-text screening, and 20 studies were included in qualitative data synthesis. The pooled analysis showed a non-significant decrease in maximum pressure under the right forefoot's metatarsus, more than the left rearfoot after local muscle fatigue at a velocity of 15 km/h (p-values = 0.48 and 0.62). The results were homogeneous and showed that local muscle fatigue did not significantly affect the right forefoot's stride frequency and length (p-values = 0.75 and 0.38). Strength training for the foot muscles, mainly focusing on the dorsiflexors, is recommended to prevent running-related injuries. Utilizing a standardized knee and ankle joint muscle fatigue assessment protocol is advised. Future experiments should focus on various shoes for running and varying foot strike patterns for injury prevention.

Why the Study is Relevant

The study aims to examine the influence of general and local muscle fatigue on kinematics and plantar pressure distribution during running.

After the first literature search and manual screening, 20 studies were included in the review, and three were included in the meta-analysis.

Limitations are related to using a treadmill in the studies and barefoot running, which does not directly reflect the same patterns of running shoes.

Furthermore, only cross-sectional studies were included, thus limiting the overall analysis of the strike patterns during running.

Summary

During running, the foot is subjected to forces equivalent to two to three times the runner's body weight. The lower extremity muscles are crucial in providing effective shock absorption to prevent incorrect or excessive loading of the passive musculoskeletal system.

When these muscles experience fatigue, their ability to adequately absorb impact forces diminishes, potentially affecting the passive musculoskeletal system and elevating the risk of running-related injuries. Over 90% of running-related issues are related to the lower extremities, with approximately one-third involving the knee, lower leg, and foot.

However, how fatigue alters foot loading is still unclear. Understanding these changes in foot loading due to fatigue is vital for tailoring injury-preventative training recommendations, particularly for runners with a history of lower extremity injuries who face an increased risk of re-injury.

The authors of this review and meta-analysis tried to examine the influence of general and local muscle fatigue on kinematics and plantar pressure distribution during running.

Key Takeaways

• Strength training of the foot muscles with a focus on dorsiflexor muscles should be done to prevent running-related injuries.
• The foot strike patterns should be varied for injury prevention to relieve the foot area under the heel.

Read the full study.

Research Title: Hallux Limitus Influence on Plantar Pressure Variations During the Gait Cycle: A Case-Control Study

Authors: Cuevas-Martinez C, Becerro-de-Bengoa-Vallejo R, Losa-Iglesias ME.

Journal: Bioengineering

Publication Year: 2023

Abstract

Background: Hallux limitus (HL) is a common foot disorder whose incidence has increased in the school-age population. HL is characterized by musculoskeletal alteration that involves the metatarsophalangeal joint, causing structural disorders in different anatomical areas of the locomotor system and affecting gait patterns. This study aimed to analyze dynamic plantar pressures in a school-aged population with functional hallux and without.

Methods: A total sample of 100 subjects (50 male and 50 female) 7 to 12 years old was included. The subjects were identified in the case group (50 subjects with HL, 22 male and 28 female) and the control group (50 subjects characterized as not having HL, 28 male and 22 female). Measurements were obtained while subjects walked barefoot and relaxed along a baropodometric platform. The HL test was realized in a seated position to sort subjects into an established study group. The variables checked in the research were the surface area supported by each lower limb, the maximum peak pressure of each lower limb, the maximum mean pressure of each lower limb, the body weight on the hallux of each foot, the body weight on the first metatarsal head of each foot, the body weight at the second metatarsal head of each foot, the body weight at the third and fourth metatarsal head of each foot, the body weight at the head of the fifth metatarsal of each foot, the body weight at the midfoot of each foot, and the body weight at the heel of each foot.

Results: Non-significant results were obtained in the variable of pressure peaks between both study groups; the highest pressures were found in the hallux with a p-value of 0.127 and in the first metatarsal head with a p-value of 0.354 in subjects with HL. A non-significant result with a p-value of 0.156 was obtained at the second metatarsal head in healthy subjects. However, significant results were observed for third and fourth metatarsal head pressure in healthy subjects with a p-value of 0.031 and regarding rearfoot pressure in subjects with functional HL with a p-value of 0.023.

Conclusions: School-age subjects with HL during gait exhibit more average peak plantar pressure in the heel and less peak average plantar pressure in the third and fourth metatarsal head compared to healthy children between 7 and 12 years old.

Why the Study is Relevant

The study aims to analyze the dynamic plantar pressure between subjects with HL and subjects without HL at school age.

The study design had a good sample size (n=100), composed of 50 males and 50 females. Of these, 50 subjects exhibited HL, while the remainder constituted the control group.

While the research question and hypothesis are interesting, standardization seems difficult. There is still no standardized method for quantitatively assessing the degree of functional HL, making it difficult to compare subjects.

Also, detailed information about how the plantar pressure gait data were chosen from different trials is needed, except for a vague indication of a relaxed and comfortable gait.

Summary

HL is defined as a limitation of the dorsiflexion movement of the first metatarsophalangeal joint. This limitation produces alterations in gait patterns because it restricts closed-kinetic-chain joint motion, causing functional limitations during the final phase of gait due to the blockage of the third rocker.

As any restriction of motion should be compensated by other anatomical points, the early detection of HL at school age is essential to prevent later compensations in adulthood.

The authors of this study tried to investigate the dynamic plantar pressure between subjects with HL and subjects without HL at school age.

Key Takeaways

• School-age subjects with HL during gait exhibit more average peak plantar pressure in the heel and less peak average plantar pressure in the third and fourth metatarsal heads compared to healthy children between 7 and 12 years old.

Read the full study.