Antonio’s Recommended Reading, Research, & Review for Human Performance - Issue #09 | November 2023

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: Efficacy of Proprioceptive Training on Plantar Pressure and Jump Performance in Volleyball Players: A Proof-of-Principle Study

Authors: Marotta N, Moggio L, Calafiore D, Prestifilippo E, Spanò R, Tasselli A, Drago Ferrante V, Invernizzi M, De Sire A, Ammendolia A.

Journal: Sensors

Publication Year: 2023

Abstract

Volleyball players are often subject to micro-traumatisms of the heel fat pad and ankle injuries. Recently, mat-based proprioceptive training has assumed a key role in recovery from these disorders. Therefore, this proof-of-principle study aimed to assess the efficacy of proprioceptive mat training on plantar pressures and athletic performance in volleyball players. The participants included adult semi-professional volleyball players allocated into two groups: an experimental group, with mat-based proprioceptive and balance training, and a control group, with a sham protocol. For the outcome, we evaluated the barefoot plantar pressure, performing an analysis on a baropodometric resistive platform. The countermovement jump and squat jump were measured using an inertial measurement unit. Nineteen subjects were included in the two groups: the active proprioceptive group (n = 10) or the control group (n = 9). The results show a more uniform redistribution of loads with pressure hindfoot relief in the experimental group compared to the control group (p = 0.021, RBC = 0.67). Moreover, we observed a significant increase in peak landing force and high concentric power development in the experimental group compared to the controls. Focused proprioceptive management provided hindfoot load attenuation by stimulating higher peaks of concentric force in the experimental group compared to the sham group. Even though the study included a small sample, the results obtained in this proof-of-principle study suggest a positive role of proprioceptive stimulation in the inter-seasonal scenario for volleyball players to improve their jump performance and reduce the micro-traumatisms of the heel fat pad and the ankle injury rate. However, further studies performed on larger samples are needed to confirm these preliminary results.

Why the Study is Relevant

The study aims to examine the effects of proprioceptive exercises on plantar pressure and jump performance in volleyball players.

The research question is based on the assumption that improvement in static pressure distribution will automatically lead to a reduction in injury risk in a dynamic environment such as a volleyball game. The study lacks a protocol for testing the dynamic pressure distribution of the players.

The design suffers from a very small sample size (n=19) and the timeframe of the intervention (2 weeks) is not enough to elicit long-lasting adaptations in the player.

Summary

Volleyball is a sport involving lateral actions in combination with complex ballistic motions in reaction to outer stimuli.

Injuries in the lower extremities are very common, especially in the foot and ankle region.

The authors of this study tried to investigate whether the use of proprioceptive exercises on specific surfaces can impact the distribution of pressure in the plantar surface of the foot and reduce the risk of injury.

Key Takeaways

• Mat-based proprioceptive training provides plantar pressure redistribution in volleyball players.
• Proprioceptive stimulation could be a safe and effective intervention to be added to the overall training program for volleyball players to reduce foot and ankle injury rates.

Read the full study.

Research Title: Plantar Pressure Is Changed To Increase Post-Impact Ball Speed During Longline Forehand and Backhand Groundstroke in Elite Female Tennis Players

Authors: Lambrich J, Muehlbauer T.

Journal: Frontiers in Sports and Active Living

Publication Year: 2023

Abstract

Introduction: Achieving high ball speed during the execution of groundstrokes represents a performance-relevant factor in tennis. However, it is unclear how plantar pressure data changes during the execution of groundstrokes by tennis players to achieve high postimpact ball speed. Thus, the objective of the present study is to determine how tennis players change the plantar pressure in each foot when they execute longline forehand and backhand groundstrokes to increase post-impact ball speed.

Methods: Seventeen healthy nationally ranked female tennis players (mean age: 21.7 ± 7.7 years) participated in this study. The players performed longline forehand and backhand groundstrokes (topspin) at four postimpact ball speed levels, i.e., at 80 km/h, 90 km/h, 100 km/h, and Vmax. Plantar pressure was measured in each foot [i.e., dominant (equals the stroke arm) and non-dominant] using flexible instrumented insoles.

Results: Irrespective of the stroke technique, the repeated measures ANOVA procedure showed significant ball speed × foot dominance interactions. For the forehand stroke, post hoc analyses revealed significantly increased (dominant foot) and decreased (non-dominant foot) pressure values when the postimpact ball speed increased from 100 km/h to vmax. For the backhand stroke, the post hoc analyses yielded significantly decreased (dominant and non-dominant foot) plantar pressure values when the postimpact ball speed increased from 100 km/h to Vmax. There were no further significant differences between the other ball speed levels.

Discussion: The significantly varying plantar pressure changes depending on the stroke technique and foot dominance to increase postimpact ball speed suggest that specific physical exercises related to the foot (dominant vs. non-dominant foot) and groundstroke (forehand vs. backhand) seem to be necessary for plantar pressure optimization.

Why the Study is Relevant

The study aims to investigate how healthy tennis players alter plantar pressure in each foot to increase postimpact ball speed during longline forehand and backhand groundstrokes.

The study design has a very applied nature as it is being performed on the court with the use of wireless insoles, trying to minimize any negative impact on the fluidity of the natural sport-specific gesture.

However, the sample size results are small (n=17). Furthermore, no information has been provided on the training status of the athlete before testing, which may potentially affect the movement pattern of the gesture on the court.

Summary

In tennis, high stroke speed is an important key performance indicator, both during serves and during groundstrokes.

Some studies have reported higher serve speed, faster groundstrokes, and higher plantar pressure values in the forehand and backhand strokes of advanced players compared with intermediate and recreational players.

The authors of this study tried to investigate changes in the movement pattern when the goal is to execute groundstrokes with increased postimpact ball speed.

Key Takeaways

• Plantar pressure data increased in the dominant foot and decreased in the non-dominant foot during the forehand stroke.
• Plantar pressure data decreased on both feet during the backhand stroke.
• Female tennis players may need specific exercises for the dominant vs. non-dominant foot and the longline forehand vs. backhand stroke.

Read the full study.

Research Title: The Impact of Anthropometric Measures on Plantar Pressure Distribution in Male Handball Players and Non-Athletes: A Cross-Sectional Study

Authors: Ameer MA, Abdel-aziem AA, Abd-Eltawab AE.

Journal: Journal of Bodywork and Movement Therapies

Publication Year: 2023

Abstract

Background: Increasing body anthropometry brings substantial spinal stress, which influences the spinal curvatures; this in turn may affect the foot plantar pressure distribution.

Objectives: This study investigated the impact of body anthropometry on static plantar pressure distribution and their relationship among handball players and non-athlete subjects.

Methods: Thirty handball players aged from 21 to 26 years, and thirty age-matched non-athletes subjects aged from 21 to 28 years participated in this study. The spinal lordosis and kyphosis angles, trunk length, pelvic tilting, and pelvic rotation were evaluated using Formetric 4-dimensions, and the Pedoscan device was used to assess the plantar pressure distribution.

Results: The handball players were significantly taller, heavier, and had a longer trunk length than the non-athletes group (p < 0.05), and a significantly increased thoracic kyphosis, forefoot pressure distribution compared to the non-athletes group (p < 0.05). The handball players had a significantly increased forefeet pressure distribution compared to the rear feet pressure distribution (p < 0.05), a high positive correlation between body height, and both trunk length and kyphosis angle (r = 0.932, 0.665 respectively), and the body height showed a high positive correlation with the forefeet pressure distribution (r = 0.665). There was a highly positive correlation between the handball players’ thoracic kyphosis and forefeet pressure distribution (r = 0.751).

Conclusions: Increasing the handball players' body height was related to increased thoracic kyphosis and forefoot pressure distribution compared to non-athlete subjects. Additionally, the kyphotic posture of handball players is associated with increasing the total forefoot pressure distribution compared to the total rear feet pressure distribution.

Why the Study is Relevant

The study aims to investigate the impact of body anthropometric characteristics (height, body weight, trunk length) on static plantar pressure distribution in male handball players.

This cross-sectional study has an acceptable minimum sample size of thirty subjects per group. However, the methods and protocols seem to have very little translation to the field as they are based on the assumption that the relationship between body anthropometry and static plantar pressure can be used to drive interventions for decreasing the risk of injury.

Summary

Handball is a team sport characterized by predominant forward flexion posture and a multitude of tackles in both offense and defense, high-intensity technical play with strength-related playing movements, and high-intensity transitions.

The authors of this study tried to investigate the influence of body anthropometric characteristics on static plantar pressure distribution and asymmetry to address imbalances and reduce injury risk.

Key Takeaways

• No significant difference between handball players and non-athletes' BMI.
• Handball players were significantly taller and heavier and with a longer trunk length compared to non-athletes.
• Handball players showed a significant increase in kyphosis compared to non-athletes.

Read the full study.