Evaluation of physical fitness in 11 years old students in Northern Italy: a powerful tool to improve physical education curricula

Purpose: This study was designed to evaluate the physical fitness (PF) in 11 years old students of 7 schools in Brescia. The aim was to provide functional data useful for motor activity promotion by physical education (PE) teaching in middle-lower school. Methods: To assess the four main components of the PF we measured: (1) anthropometric data, i.e. height (m), weight (kg) to calculate BMI (kg/m2); (2) aerobic fitness through the six minutes walking test (6MWT); (3) muscular fitness through the standing broad jump test (SBJT); (4) joint flexibility from the V-Sit and reach test (VSR). Statistical analysis was performed by 2-way ANOVA. Results: 349 children were tested, 257 Italian (I) and 74 Not-Italian (NI); I: 127 males (M) and 130 females (F); NI: 41 M and 33 F. NI children belonged to different ethnic groups. BMI I-M (19.3 +- 3.3) I-F (19.5 +- 3.7) NI-M (20.7 +- 3.6) NI-F (19.9 +- 4.5) 6MWT I-M (720 +- 59) I-F (697 +- 54) NI-M (704 +- 75) NI-F (683 +- 52) SBJT I-M (154 +- 22) I-F (144 +- 21) NI-M (145 +- 24) NI-F (137 +- 21) VSR I-M (- 7 +- 7) I-F (4 +-10) NI-M (- 5 +- 8) NI-F (- 1 +- 10) Statistical differences between groups. BMI I vs NI; M-I vs M-NI; SBJT I vs NI; M(I + NI) vs F(I + NI); M-I vs F-I; VSR M(I + NI) vs F(I + NI); M(I) vs F(I) Conclusions: I group data. BMI mean value of both M and F is close to the 50th percentile according to a previous study concerning North of Italy children. Nonetheless, 15% of M and 11% of F have to be considered overweight [1]. 6MWT and SBJT mean results are even better than those reported for other age-matched European children [2, 3]. VSR data are strongly influenced by gender. M show marked negative results, while F show good flexibility. This difference should be considered in PE curriculum. NI group data. Only two of the PF descriptors are different compared to I data, being BMI and SBJT value higher and lower, respectively, than those of I counterpart. Generally, the resulting overall PF of the investigated students is in line with the literature data. The level of PF can be considered adequate, making this population able to follow PE curriculum aimed to include physical activity in daily life as a tool to discourage its abandon in adulthood. References Cacciari E et al (2002) Eur J Clin Nutr 56:171–180 Ulrich S et al (2013) BMC Pulm Med 13:49–60 Ortega FB et al (2011) Br J Sports Med 45:20–2

Motor unit conduction velocity at different joint angles

Purpose: The aim of this study was to evaluate the dependence of motor unit conduction velocity (MUCV) on the length of the muscle. Methods: Muscle length was modified considering three different ankle angles: 90°,110° and 130°. For each angle the maximal voluntary contraction (MVC) was measured during static ankle dorsiflexion. High-density surface electromyography (HD-sEMG, 128 channels) was recorded from the tibialis anterior muscle (TA) in six young individuals. Subjects executed a volitional effort in which the output tension changed in a trapezoidal ramp fashion (15 s transient and 40 s steady contraction). Two levels of steady contraction were investigated: 10% and 20% of MVC. Using a novel decomposition technique based on HD-sEMG processing (Negro et al. 2016), the individual MUCV values were estimated during the trapezoid steady part. The decomposition was performed at each ankle angle independently, and the MU action potentials were not tracked across different muscle lengths. Results: MVC mean values at 90° and 130° were 91.78% and 78.77% of 110° value respectively. Considering that there was no statistical difference between the MUCV estimations calculated at 10 and 20% MVC, the values were grouped. The average CV was 4.00 ± 0.54 m/ s for 90°, 3.88 ± 0.19 m/s for 110° and 3.77 ± 0.37 m/s for 130°. One-Way Anova analysis showed a weak effect between the three conditions (P = 0.04). Conclusion: MUCV changes were weakly related to the different muscle lengths. Explanation of our results should consider that the muscle fiber can be approximated as a constant volume system and that, from the cable theory, the smaller the diameter the lower the CV is. On these bases, the reduction of muscle fibers transverse diameter during muscle elongation when the ankle angle increases from 90° to 130° could be a possible explanation for our results

Muscle contractile properties directly influence shared synaptic inputs to spinal motor neurons

Alpha band oscillations in shared synaptic inputs to the alpha motor neuron pool can be considered an involuntary source of noise that hinders precise voluntary force production. This study investigated the impact of changing muscle length on the shared synaptic oscillations to spinal motor neurons, particularly in the physiological tremor band. Fourteen healthy individuals performed low-level dorsiflexion contractions at ankle joint angles of 90° and 130°, while high-density surface electromyography (HDsEMG) was recorded from the tibialis anterior (TA). We decomposed the HDsEMG into motor units spike trains and calculated the motor units’ coherence within the delta (1–5 Hz), alpha (5–15 Hz), and beta (15–35 Hz) bands. Additionally, force steadiness and force spectral power within the tremor band were quantified. Results showed no significant differences in force steadiness between 90° and 130°. In contrast, alpha band oscillations in both synaptic inputs and force output decreased as the length of the TA was moved from shorter (90°) to longer (130°), with no changes in delta and beta bands. In a second set of experiments (10 participants), evoked twitches were recorded with the ankle joint at 90° and 130°, revealing longer twitch durations in the longer TA muscle length condition compared to the shorter. These experimental results, supported by a simple computational simulation, suggest that increasing muscle length enhances the muscle's low-pass filtering properties, influencing the oscillations generated by the Ia afferent feedback loop. Therefore, this study provides valuable insights into the interplay between muscle biomechanics and neural oscillations

Sex-differences in the longitudinal recovery of neuromuscular function in COVID-19 associated acute respiratory distress syndrome survivors

IntroductionPatients admitted to the intensive care unit (ICU) following severe acute respiratory syndrome 2 (SARS-CoV-2) infection may have muscle weakness up to 1 year or more following ICU discharge. However, females show greater muscle weakness than males, indicating greater neuromuscular impairment. The objective of this work was to assess sex differences in longitudinal physical functioning following ICU discharge for SARS-CoV-2 infection.MethodsWe performed longitudinal assessment of physical functioning in two groups: 14 participants (7 males, 7 females) in the 3-to-6 month and 28 participants (14 males, 14 females) in the 6-to-12 month group following ICU discharge and assessed differences between the sexes. We examined self-reported fatigue, physical functioning, compound muscle action potential (CMAP) amplitude, maximal strength, and the neural drive to the tibialis anterior muscle.ResultsWe found no sex differences in the assessed parameters in the 3-to-6-month follow-up, indicating significant weakness in both sexes.Sex differences emerged in the 6-to-12-month follow-up. Specifically, females exhibited greater impairments in physical functioning, including lower strength, walking lower distances, and high neural input even 1 year following ICU-discharge.DiscussionFemales infected by SARS-CoV-2 display significant impairments in functional recovery up to 1 year following ICU discharge. The effects of sex should be considered in post-COVID neurorehabilitation

Electrophysiological neuromuscular alterations and severe fatigue predict long-term muscle weakness in survivors of COVID-19 acute respiratory distress syndrome

IntroductionLong-term weakness is common in survivors of COVID-19-associated acute respiratory distress syndrome (CARDS). We longitudinally assessed the predictors of muscle weakness in patients evaluated 6 and 12 months after intensive care unit discharge with in-person visits.MethodsMuscle strength was measured by isometric maximal voluntary contraction (MVC) of the tibialis anterior muscle. Candidate predictors of muscle weakness were follow-up time, sex, age, mechanical ventilation duration, use of steroids in the intensive care unit, the compound muscle action potential of the tibialis anterior muscle (CMAP-TA-S100), a 6-min walk test, severe fatigue, depression and anxiety, post-traumatic stress disorder, cognitive assessment, and body mass index. We also compared the clinical tools currently available for the evaluation of muscle strength (handgrip strength and Medical Research Council sum score) and electrical neuromuscular function (simplified peroneal nerve test [PENT]) with more objective and robust measures of force (MVC) and electrophysiological evaluation of the neuromuscular function of the tibialis anterior muscle (CMAP-TA-S100) for their essential role in ankle control.ResultsMVC improved at 12 months compared with 6 months. CMAP-TA-S100 (P = 0.016) and the presence of severe fatigue (P = 0.036) were independent predictors of MVC. MVC was strongly associated with handgrip strength, whereas CMAP-TA-S100 was strongly associated with PENT.DiscussionElectrical neuromuscular abnormalities and severe fatigue are independently associated with reduced MVC and can be used to predict the risk of long-term muscle weakness in CARDS survivors

Identification of innovative tools for the electromechanical evalutation of the neuro-muscular function in patients with altered motor control during daily-life activities and adapted physical activities

Identification of innovative tools for the electromechanical evalutation of the neuro-muscular function in patients with altered motor control during daily-life activities and adapted physical activitiesIdentification of innovative tools for the electromechanical evalutation of the neuro-muscular function in patients with altered motor control during daily-life activities and adapted physical activitie

THE LINK BETWEEN PHYSICAL PERFORMANCE AND SELF-EFFICACY: HOW MUCH CAN I JUMP?

This study evaluated the reliability of self-efficacy in predicting squat jump performance in young adults. Participants completed a questionnaire and performed three jumps while their actual jump height was measured. Results showed no significant differences between predicted and actual performance, but a trend of under- and overestimation was observed. Self-efficacy assessment methods were found to be reliable and repeatable and may be a valuable tool for modifying and adapting training routines

Exploring shuttle run test performance and adiposity indices among Italian high school students: a comparative analysis with European norms

Despite the recent decline in physical fitness, only a few studies were conducted on speed-agility (SA) trends and they have contrasting results about the trend of SA. Therefore, the aim of this study was to evaluate the SA performance of Italian high school students and to compare the results with European normative data. Furthermore, we analyzed how the adiposity indices were related to SA performance in adolescents to help coaches and physical education teachers to better tailor their activities. A total of 627 high school students aged between 14 to 18 years were recruited in 2019 from a single high school in Northern Italy. To assess SA we used the 10x5m shuttle run test, while to evaluate anthropometric characteristics we assessed weight, height, waist circumference, BMI, Waist-to-height ratio, TMI and fat mass. SA performance was found higher only for 15 years old males and for 14 and 15 years old female groups, while no differences were found for other age groups. Age-related performance shows no differences between male and female students. The correlation between the anthropometric indices and SA performance showed a poor relation (p<0.01) for males but not for females. We found that the SA seems poorly related to anthropometric characteristics and age (ranging from 14 to 18). In addition, our results showed that the SA performance of Italian adolescents is similar to, or even better than, the normative data from Europe. These results provide crucial information for physical education teachers to promote and evaluate SA in high school students