The foot arch and viscoelastic properties of plantar fascia and Achilles tendon

Plantar fascia reduces ground reaction force on metatarsal heads. It serves to stiffen medial and lateral longitudinal arches and reduce longitudinal arch flattening. Mechanical characteristics of plantar fascia and Achilles tendon can provide significant information on fascia and tendon functional condition as well as the risks of irregularities. The objectives of this study were: (a) to identify plantar fascia and Achilles tendon oscillation frequency, decrement and stiffness, and to evaluate the reliability of differences between normal, low and high foot arch; (b) to identify the relation between plantar fascia and Achilles tendon mechanical characteristics. 42 feet of 21 soccer players were investigated in order to determine plantar fascia and Achilles tendon oscillation frequency, decrement and stiffness of feet with normal, low and high foot arch. 164 feet of 32 soldiers, 21 football players and 29 basketball players were analyzed to determine the link between plantar fascia and Achilles tendon mechanical characteristics. The medial longitudinal foot arch was evaluated according to arch index by Williams (WAI). The Achilles tendon and plantar fascia oscillation frequency, decrement and stiffness were evaluated using Myoton-3 system. This study revealed that relaxed plantar fascia of feet with normal arch is statistically reliably more elastic than fascia of feet with low arch. A very strong relationship was discovered between mechanical characteristics of plantar fascia and Achilles tendon

The foot arch and viscoelastic properties of plantar fascia and Achilles tendon

Plantar fascia reduces ground reaction force on metatarsal heads. It serves to stiffen medial and lateral longitudinal arches and reduce longitudinal arch flattening. Mechanical characteristics of plantar fascia and Achilles tendon can provide significant information on fascia and tendon functional condition as well as the risks of irregularities. The objectives of this study were: (a) to identify plantar fascia and Achilles tendon oscillation frequency, decrement and stiffness, and to evaluate the reliability of differences between normal, low and high foot arch; (b) to identify the relation between plantar fascia and Achilles tendon mechanical characteristics. 42 feet of 21 soccer players were investigated in order to determine plantar fascia and Achilles tendon oscillation frequency, decrement and stiffness of feet with normal, low and high foot arch. 164 feet of 32 soldiers, 21 football players and 29 basketball players were analyzed to determine the link between plantar fascia and Achilles tendon mechanical characteristics. The medial longitudinal foot arch was evaluated according to arch index by Williams (WAI). The Achilles tendon and plantar fascia oscillation frequency, decrement and stiffness were evaluated using Myoton-3 system. This study revealed that relaxed plantar fascia of feet with normal arch is statistically reliably more elastic than fascia of feet with low arch. A very strong relationship was discovered between mechanical characteristics of plantar fascia and Achilles tendon

The effects of high-velocity hamstring muscle training on injury prevention in football players

Background: Explosive and fast body movements, sprints, jumps and quick changes of direction, which are characteristic of the football training, place considerable strain on the hamstring muscles. Due to the high occurrence of hamstring injuries, new preventive strategies are required that focus on high-velocity training. The purpose was to assess the effectiveness of high-velocity elastic-band training in reducing the occurrence of hamstring injuries in football players.Methods: Male football players from 15 teams (n = 319) playing in national competitions participated in this study. The players were involved in a 5-week exercise period in either the intervention group (INT) or the control group (CON), with a follow-up period of ∼4 months where hamstring injuries and exposure time were recorded. The INT group had two to three sessions per week of elastic-band training with low-load, high-velocity leg curls while lying prone; the CON group performed self-paced football-specific drills.Results: The incidence rate of hamstring injuries was 6.5% in the INT group (8 out of 123 players) and 9.2% in the CON group (18 out of 196 players). Although the INT group showed almost 1/3 reduction in hamstring injury incidence compared to the CON group, the difference was not statistically significant (p > 0.05). Moreover, no differences (p > 0.05, odds ratio [OR] = trivial-to-small) in distribution between the groups were found in hamstring injury characteristics (leg dominance and mechanism) except for the distribution of injuries that occurred during matches or training (p = 0.036; OR = 6.14, moderate).Conclusion: The program of high-velocity elastic-band training did not prove to be effective in preventing hamstring muscle injuries in football players despite displaying some positive indications that could be considering when creating injury prevention programs

Obesity-related reduced spirometry and altered breathing pattern are associated with mechanical disadvantage of the diaphragm

The aim of this study was to characterize the breathing patterns of individuals with obesity during routine activities such as sitting and standing, and to identify potential contributors to alterations in these patterns. Measurements performed in 20 male subjects with obesity (BMI, 31.8±1.5 kg/m2) and 20 controls (BMI, 23.5±1.4 kg/m2) included anthropometric parameters, breathing-patterns in sitting and standing positions, spirometry, maximal respiratory pressures, and diaphragm B-mode ultrasonography. Individuals with obesity exhibited lower tidal volume and increased respiratory rate to maintain a similar minute-ventilation (p<0.05). Subjects with obesity demonstrated impaired spirometry and respiratory muscle strength, with inspiratory functions being notably compromised (p<0.05). Individuals with obesity had a greater diaphragm thickness at end inspiration but lower thickening-fraction at end quiet and forced breathings and reduced diaphragmatic displacement and excursion during maximal breaths (p<0.05). BMI was negatively associated with all respiratory function markers (p<0.05). Individuals with obesity exhibit a higher respiratory rate but lower tidal volume, likely to accommodate decreased compliance and excess thoracic and abdominal fat, further hindering inspiratory function. Moreover, increased adiposity is associated with a thicker but weaker diaphragm, primarily due to the diaphragm's mechanical disadvantage rather than its intrinsic inability to generate force

Is sight the main deterrent to race performance in visually impaired competitive swimmers?

status: publishe

Freestyle Race Patterns in Paralympic Swimmers with Varying Impairments

status: publishe

Riding a Mechanical Scooter from the Inconvenient Side Promotes Muscular Balance Development in Children

Mechanical scooter riding is a popular physical activity among children, but little is known about the differences in muscle loading between the dominant and non-dominant sides during this activity. The objective of this study was to identify the muscle activation patterns in children’s dominant and non-dominant legs as they rode scooters on the convenient and inconvenient sides. The study included nine healthy children aged 6–8. The participants rode 20 m on a mechanical scooter at a self-selected pace using both the convenient and inconvenient sides. Electromyography was used to measure the muscle activity in the dominant and non-dominant legs during the pushing and gliding phases. A 20 m sprint run was used as a control exercise to estimate the typical differences in muscle activation between the dominant and non-dominant legs. In the pushing phase, the symmetry index for five of the eight analyzed muscles exceeded 50% (p p < 0.05). Upon observing children who changed sides while riding a scooter, it was found that the pattern of muscle activation displayed a reverse trend that resembled the initial pattern. Our study indicated notable differences in muscle activity patterns between the dominant and non-dominant sides of individual leg muscles during children’s scooter riding. These patterns were reversed when children switched sides on the scooter. These findings suggest that using both legs and switching sides while riding a scooter may be a viable strategy for promoting balanced muscular development

The role of age on neuromuscular performance decay induced by a maximal intensity sprint session in a group of competitive endurance athletes

Age -related changes in the neuromuscular system functions may affect profoundly high -level athletes ' performance across their career s. The present study aimed to analyse the fatiguing effect of a maximal intensity sprint session (MISS) on competitive athletes of diffe rent age s. Thirty - one competitive endurance athletes completed a knee extensors and flexors ' maximal -voluntary- isometric -contraction (MVC) test before and after a maximal -intensity -sprint -session (MISS) consisting of 4x15s Wingate -tests. The data have been stratified considering three age categories (18 -28, n=11, 29- 38; n=10; 39 -43, n=10). Overall, both quadricep and hamstring muscles early and late rate of torque development (RTD) dropped significantly more than the maximal voluntary torque (MVT) (p<.05). Age had a significant effect on early RTD , with older athletes exhibiting greater RTD (p<.05). A significant effect of age also emerged for the changes in surface sEMG variables, in which the frequency spectrum variables dropped significantly more than the sEMG amplitude (RMS) (p<.05). The dynamics of changes in neuromuscular performance markers after a MISS suggested that getting older competitive athletes may potentially experience a greater loss in early explosive strength compared to maxim al or late exp losive strength

Slow torque recovery after eccentric exercise and the repeated bout effect; the role of primary and secondary muscle damage

Objectives: To determine the role of primary and secondary damage in the variation between people of maximum voluntary contraction (MVC) torque recovery following eccentric exercise and the faster recovery following a repeated bout of exercise. Methods: Twenty-one healthy, active but untrained young female subjects undertook eccentric exercise of the elbow flexors and 11 repeated the exercise 28 days later. Changes of MVC torque and creatine kinase (CK) were followed for 7 days after each bout of exercise. Results: Following the first bout, 45% of subjects showed a continuing decline in MVC torque, suggesting secondary damage, which was correlated with a large delayed CK release (R 2 =0.54, p<0.001). After the second bout of exercise, the initial MVC torque loss was similar to that after the first bout while torque recovery was faster, but only for the previously slow recovering subjects. Comparing the time course of MVC torque recovery of first and second bouts suggests secondary damage develops over 4 days. Conclusions: The data are consistent with primary damage being similar between subjects and unaffected by the repeated bout while it is secondary damage which accounts for differences in MVC torque recovery and is suppressed following a repeated bout of exercise