Antonio’s Recommended Reading, Research, & Review for Human Performance - Issue #08 | July 2023

Every month, 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: Plantar pressure sensors indicate women to have a significantly higher peak pressure on the hallux, toes, forefoot, and medial of the foot compared to men

Authors: Yamamoto T, Hoshino Y, Kanzaki N, Nukuto K, Yamashita T, Ibaraki K, Nagamune K, Nagai K, Araki D, Matsushita T, and Kuroda R

Journal: Journal of Foot & Ankle Research

Publication Year: 2020

Abstract

Background: Sex-related differences in plantar pressure distribution during activities should be thoroughly inspected as it can help establish treatment and prevention strategies for foot and ankle problems. In-shoe measurement systems are preferable without space and activity restrictions; however, previously reported systems are still heavy and bulky and induce unnatural movement. Therefore, a slim and light plantar pressure sensor was newly developed to detect the effect of sex differences on plantar pressure during standing and walking.

Methods: One-hundred healthy adult volunteers (50 women and 50 men) were recruited. Ten plantar pressure sensors were implanted in a 1-mm thick insole weighing 29 g. Plantar pressure was recorded at 200 Hz during 3 s of standing and walking ten steps. The maximum loads during standing and walking were analyzed in each sensor, and the results were compared between different areas of the foot in the anteroposterior direction, the mediolateral direction, and between different time points. The movement of the center of pressure (CoP) during walking was also evaluated. Analyses were adjusted for body mass index (BMI) and gait speed.

Results: The movement of CoP was constant for both sexes. In all cases, the maximum load was observed on the medial of the foot. Women had a significantly higher peak pressure on the hallux, toes, forefoot, and medial aspect of the foot than men while standing and walking (p < .05).

Conclusions: A newly introduced in-shoe plantar pressure sensor demonstrated the foot's typical loading transition pattern. Furthermore, higher plantar pressure in the forefoot was detected in healthy women compared to men during standing and walking activities.

Why the Study Is Relevant

The study aims to evaluate pressure distribution on the sole during gait and stance using an in-shoe pressure measurement system in order to compare results between sexes and examine the effects of sex differences on plantar pressure.

Although the study has a very good sample size (n=100), several limitations need to be considered when interpreting the results.

The most relevant limitations concern the plantar pressure system used and data collection.

The in-shoe plantar pressure system has few sensors (n=10), and no information about accuracy, pressure range, and resolution has been shared.

Regarding data collection, the measurement has been done with shoes, and this factor needs to consider that shoes can affect an individual foot strike dynamics in different ways, so it becomes difficult to draw generalized conclusions on pressure distribution differences between men and women.

Summary

Analyzing the load on the plantar surface during walking and running is essential for sports performance, injury prevention, footwear designs, and also for the diagnosis of diseases.

The study's authors tried to investigate whether a difference exists in plantar pressure distribution between women and men during dynamic activities.

Key Takeaways

• Women put more pressure on the front and medial side of the foot with respect to men during walking and standing.
• Women apply significantly higher peak pressure on the hallux, toes, forefoot, and medial aspect of the foot compared to men while walking.
• Women have a higher pelvic tilt compared to men.

Read the full study.

Research Title: Plantar pressure evaluation during the season in five basketball movements

Authors: Amaro CM, Castro MA, Roseiro L, Neto MA, and Amaro AM

Journal: Applied Sciences

Publication Year: 2020

Abstract

Sports activity is essential in health, with a clear motivation for its practice. One sport involving more athletes is basketball, where the human body undergoes rapid reactions, emphasizing the contact of the foot with the ground. The main goal of this study is to evaluate the distribution of plantar pressure in five different basketball movements. Supported by a group of nine volunteer female athletes from a senior basketball team, a data acquisition protocol was defined to identify changes throughout the sports season.

In this study, the maximum values of plantar pressure were evaluated for both feet. The five movements that were defined and studied are all movements that might be performed during the basketball practice period. At least seven repetitions were performed for each movement to guarantee the necessary data reliability and repeatability conditions. These occurred at two different moments of the sports season: at the beginning of the competitive in November and during the season's peak four months later, in March.

Overall, the results did not present statistically significant changes between the two seasons in this study. However, a slight decrease was observed throughout the sporting season for all movements, except for the rebound, with a contrary evaluation. Additionally, athletes with a higher experience level showed higher plantar pressure values than less experienced athletes.

Why the Study Is Relevant

The study aims to evaluate plantar pressure in five different basketball-specific movements in two moments of the season, at the beginning and at the peak of the competition season.

The study's main advantage relies on its very applied nature, as the authors measured plantar pressure on the court during sport-specific movements instead of measuring in a lab-controlled environment.

The study's main limitation is the minimal sample size (n=11).

Summary

The level of competition, intensity, and density of games in basketball has increased in recent years, increasing the risk of injury.

Ankle injuries represent the most frequent injured site, and female players seem to suffer from the greatest incidence of lower limb injuries concerning men.

Plantar pressure distribution analysis may help coaches and sports medicine professionals diagnose lower limb problems and prevent injury.

The study's authors tried to investigate plantar pressure distribution in five basketball-specific movements to establish pressure profiles and identify potential patterns of increased risk of injury.

Key Takeaways

• No significant statistical differences in plantar pressure distribution between the beginning of the season and the peak of the competitive season.
• At the beginning of the competitive season, plantar pressure values were higher for all the movements except the rebound.
• In rebound movement, pressure values were higher at the peak of the competitive season.

Read the full study.

Research Title: The arch-support insoles show benefits to people with flatfoot on stance time, cadence, plantar pressure and contact area

Authors: Huang YP, Peng HT, Wang X, Chen ZR, and Song CY

Journal: PLOS One

Publication Year: 2020

Abstract

Background: Pes planus (flatfoot) is a common deformity characterized by the midfoot arch collapsing during walking. As the midfoot is responsible for shock absorption, persons with flatfoot experience an increased risk of injuries such as thumb valgus, tendinitis, plantar fasciitis, metatarsal pain, knee pain, lower back pain with prolonged uphill, downhill, and level walking, depriving them of the physical and mental health benefits of walking as an exercise.

Methods: Fifteen female college students with flatfoot were recruited. A wireless plantar pressure system measured the stance time, cadence, plantar pressure, and contact area. Parameters were compared between wearing flat and arch-support insoles using a two-way repeated measures ANOVA on an incline, decline, and level surface, respectively. The significance level α was set to 0.05. The effect size (ES) was calculated as a measure of the practical relevance of the significance using Cohen's d.

Results: On a level surface, the stance time in the arch-support insole was significantly shorter than in the flat insole (p<0.05; ES = 0.48). The peak pressure of the big toe in the arch-support insole was considerably more significant than in the flat insole on the uphill (p<0.05; ES = 0.53) and level surfaces (p<0.05; ES = 0.71). The peak pressure of the metatarsals 2-4 and the midfoot contact area in the arch-support insole were significantly greater than in the flat insole on all surfaces (all p< 0.05).

Conclusions: These results imply that wearing an arch-support insole benefits the shortened stance time and generation of propulsion force to the big toe while walking on uphill and level surfaces and to the metatarsals 2-4 while walking on a level surface. More evenly distributed contact areas across the midfoot may help absorb shock during uphill, downhill, and level walking.

Why the Study Is Relevant

The study aims to investigate the effects of the arch-support insoles on stance time, cadence, peak pressure, and contact area of the foot while walking uphill, downhill, and on a level surface, respectively.

The study suffers from a few evident limitations, as follows:

• The sample size is very small (n=15).
• Tasks have been performed on a treadmill within a lab environment, making the results not transferable to what happens while walking outdoors.
• The diagnosis of flatfoot has been made based exclusively on a static footprint index, with no investigation on the different causes of flatfoot and no information about changes during dynamic activities.

Summary

Pes planus is a common symptom among many dysfunctions associated with the foot, and its prevalence is estimated to be 16.2% among males and 11.7% among females. Flatfoot results from a lack of foot arch support, insufficient flexibility of the plantar ligaments and tendons, and the collapse of the foot's medial arch.

Individuals with flatfoot have trouble engaging in prolonged running because of a lack of foot arch support and shock dissipation.

The study's authors tried to investigate if a benefit exists in wearing arch-support insoles for individuals showing a flatfoot deformity.

Key Takeaways

• Wearing an arch-support insole provides benefits in the shortened stance time.
• Arch-support insoles help absorb shock at the medial heel during walking.
• Arch-support insoles facilitate a more evenly distributed contact area over the entire foot.

Read the full study.