scholarly journals Can the Neuromuscular Performance of Young Athletes Be Influenced by Hormone Levels and Different Stages of Puberty?

2020 ◽  
Vol 17 (16) ◽  
pp. 5637 ◽  
Author(s):  
Paulo Francisco de Almeida-Neto ◽  
Dihogo Gama de Matos ◽  
Vanessa Carla Monteiro Pinto ◽  
Paulo Moreira Silva Dantas ◽  
Tatianny de Macêdo Cesário ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Young People ◽  
Young Male ◽  
Lower Limbs ◽  
Young Athletes ◽  
Testosterone Levels ◽  
Neuromuscular Performance ◽  
Lower Limb Strength ◽  
Determining Factor ◽  
Hormonal Levels

Background: Endocrine mechanisms can be a determining factor in the neuromuscular performance of young athletes. Objective: The objective of the present study was to relate maturational and hormonal markers to neuromuscular performance, as well as to verify whether young athletes with different testosterone levels show differences in muscle strength. Methods: The sample consisted of 37 young male Brazilian athletes (11.3 ± 0.94 years) who were members of a sports initiation project. Hormonal markers were analyzed biochemically by blood samples, and maturation markers by mathematical models based on anthropometry. Body composition was verified by tetrapolar bioimpedance. The performance of upper and lower limb strength and body speed were analyzed. Results: Hormonal and maturational markers were related to neuromuscular performance (p < 0.05). Young people with higher testosterone levels showed higher muscle strength (p < 0.05). Artificial neural networks showed that testosterone predicted the performance of upper limbs by 49%, and maturation by 60%. Maturation foreshadowed the performance of lower limbs by 30.3%. Conclusion: Biological maturation and hormonal levels can be related to neuromuscular performance, and young people with higher testosterone levels show superior muscle strength in relation to the others.

scholarly journals COVID-19 era in long-term cardiac rehabilitation programs: how was muscle strenght and lean mass affected in cardiovascular patients?

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
M Borges ◽  
M Lemos Pires ◽  
R Pinto ◽  
G De Sa ◽  
I Ricardo ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Cardiac Rehabilitation ◽  
Lean Mass ◽  
Lower Limb ◽  
Lower Limbs ◽  
Phase Iii ◽  
Face To Face ◽  
Home Based ◽  
Lower Limb Strength

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Exercise prescription is one of the main components of phase III Cardiac Rehabilitation (CR) programs due to its documented prognostic benefits. It has been well established that, when added to aerobic training, resistance training (RT) leads to greater improvements in peripheral muscle strength and muscle mass in patients with cardiovascular disease (CVD). With COVID-19, most centre-based CR programs had to be suspended and CR patients had to readjust their RT program to a home-based model where weight training was more difficult to perform. How COVID-19 Era impacted lean mass and muscle strength in trained CVD patients who were attending long-term CR programs has yet to be discussed. Purpose To assess upper and lower limb muscle strength and lean mass in CVD patients who had their centre-based CR program suspended due to COVID-19 and compare it with previous assessments. Methods 87 CVD patients (mean age 62.9 ± 9.1, 82.8% male), before COVID-19, were attending a phase III centre-based CR program 3x/week and were evaluated annually. After 7 months of suspension, 57.5% (n = 50) patients returned to the face-to-face CR program. Despite all constraints caused by COVID-19, body composition and muscle strength of 35 participants (mean age 64.7 ± 7.9, 88.6% male) were assessed. We compared this assessment with previous years and established three assessment time points: M1) one year before COVID-19 (2018); M2) last assessment before COVID-19 (2019); M3) the assessment 7 months after CR program suspension (last trimester of 2020). Upper limbs strength was measured using a JAMAR dynamometer, 30 second chair stand test (number of repetitions – reps) was used to measure lower limbs strength and dual energy x-ray absorptiometry was used to measure upper and lower limbs lean mass. Repeated measures ANOVA were used. Results Intention to treat analysis showed that upper and lower limbs lean mass did not change from M1 to M2 but decreased significantly from M2 to M3 (arms lean mass in M2: 5.68 ± 1.00kg vs M3: 5.52 ± 1.06kg, p = 0.004; legs lean mass in M2: 17.40 ± 2.46kg vs M3: 16.77 ± 2.61kg, p = 0.040). Lower limb strength also decreased significantly from M2 to M3 (M2: 23.31 ± 5.76 reps vs M3: 21.11 ± 5.31 reps, p = 0.014) after remaining stable in the year prior to COVID-19. Upper limb strength improved significantly from M1 to M2 (M1: 39.00 ± 8.64kg vs M2: 40.53 ± 8.77kg, p = 0.034) but did not change significantly from M2 to M3 (M2 vs M3: 41.29 ± 9.13kg, p = 0.517). Conclusion After CR centre-based suspension due to COVID-19, we observed a decrease in upper and lower limbs lean mass and lower limb strength in previously trained CVD patients. These results should emphasize the need to promote all efforts to maintain physical activity and RT through alternative effective home-based CR programs when face-to-face models are not available or possible to be implemented.

scholarly journals Influence of skeletal maturation on physical fitness of young people with Down syndrome

2020 ◽  
Vol 34 (3) ◽  
pp. 373-383
Author(s):  
Everaldo Lambert Modesto ◽  
Leonardo dos Santos Oliveira ◽  
Bruna Barboza Seron ◽  
Eloise Werle de Almeida ◽  
Márcia Greguol
Keyword(s):  
Down Syndrome ◽  
Resistance Training ◽  
Muscle Strength ◽  
Young People ◽  
Physical Fitness ◽  
Intervention Program ◽  
Training Group ◽  
Lower Limbs ◽  
Skeletal Maturation ◽  
Control Group

Individuals with Down syndrome (DS) tend to prematurely reach the skeletal maturation period. In addition, young people with this condition have poor physical fitness and few opportunities to practice physical activity when compared to those without disabilities. The aim of this study was to investigate the skeletal maturation of young people with Down syndrome and its influence on the behavior of physical fitness related to health, after aerobic and resistance training programs. Forty people with DS, with an average age of 15.4 (± 2.6) years, were divided into three groups for a 12 weeks intervention program, AT - aerobic training group (3 times/week; 50 minutes/session), RT - resistance training group (twice/week ; 50 minutes/session) and CG - control group, 9 participants. Determination of skeletal age (EA) was performed using the Greulich-Pyle method. Anthropometric variables, muscle strength and peak VO2 were measured pre and post intervention. It was found that skeletal maturation influenced the effects of training, only being significant for body weight and strength in the upright row variables. In addition, the muscle strength of upper and lower limbs increased significantly after 12 weeks of aerobic or resistance training. Then, we can conclude that the effects of physical training on physical fitness of young people with Down syndrome appear to improve as the bone age increases.

scholarly journals Effect of Vibration Massage and Passive Rest on Recovery of Muscle Strength after Short-Term Exercise

2021 ◽  
Vol 18 (21) ◽  
pp. 11680
Author(s):  
Wiesław Chwała ◽  
Paweł Pogwizd ◽  
Łukasz Rydzik ◽  
Tadeusz Ambroży
Keyword(s):  
Muscle Strength ◽  
Recovery Period ◽  
Study Groups ◽  
Lower Limbs ◽  
Short Term ◽  
Vibration Effect ◽  
Lower Limb Strength ◽  
Group Contraction ◽  
Muscle Groups ◽  
Study Participants

Background: The aim of the study was to compare the effect of vibration massage and passive rest on accelerating the process of muscle recovery after short-term intense exercise. Methods: Eighty-four healthy men aged 20 to 25 years participated in the study. Study participants performed isometric (ISO-M Group) and auxotonic (AUX-M group) contraction exercise in the lower limbs. Vibration massage was administered after exercise in the first recovery period. In the same period, controls rested passively, without the support of vibration massage. To assess the effectiveness of the applied vibration, a 4-fold measurement of the maximum force of the muscles involved in the exercise was performed under conditions of isometric contractions on a leg press machine set at an angle of 45° degrees upwards. Results: Differences in maximum strength during isometric contraction were found compared to baseline in favor of the groups subjected to the experimental vibration massage. Differences were demonstrated in muscle strength between the study groups (p < 0.005). The second period of passive rest in all groups did not bring significant changes in the values of maximal lower limb strength. Conclusions: Properly selected characteristics of the vibration effect can be an effective method in accelerating recovery and regaining lost motor capabilities of muscle groups fatigued by exercise. This offers the potential to shorten rest periods between sets of repetitions in training or between training units.

scholarly journals Lean mass and biological maturation as predictors of muscle power and strength performance in young athletes

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254552
Author(s):  
Paulo Francisco de Almeida-Neto ◽  
Rafaela Catherine da Silva Cunha de Medeiros ◽  
Dihogo Gama de Matos ◽  
Adam D. G. Baxter-Jones ◽  
Felipe J. Aidar ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Power ◽  
Bone Age ◽  
Lower Limbs ◽  
Height Velocity ◽  
Upper Limbs ◽  
Young Athletes ◽  
Adolescent Athletes ◽  
Network Analyses ◽  
Biological Maturation

Background The biological maturation (BM) analyzed by peak height velocity (PHV) and bone age (BA), and lean body mass has been associated with the strength and muscle power of young athletes. However, the ability of BM (PHV and BA) and LM markers to predict muscle strength and power in young athletes remains uncertain. Objective The Aim was determine the predicting power of BM markers (PHV and BA) and LM in relation to muscle power of upper and lower limbs and muscle strength of upper limbs in adolescent athletes at puberty. Methods Ninety-two adolescent athletes (both sexes; age 12.4 ± 1.02 years) were assessed for body composition by dual-energy X-ray absorptiometry (DXA). Power of upper limbs (ULP), force handgrip (HG), vertical jump (VJ) and countermovement jump (CMJ) were recorded. BM was predicted by mathematical models to estimate PHV and BA. Multilayer artificial neural network analyses (MLP’s) were used to determine the power of prediction of LM, PHV and BA on muscle power and strength of upper- and lower-limbs of the athletes. Results LM, BA and PHV were associated with HG (r>0.74, p<0.05) and ULS (r>0.60, p<0.05) in both sexes. In both sexes BA was associated with VJ (r>0.55, p<0.05) and CMJ (r>0.53, p<0.05). LM indicated associations (r>0.60, p<0.05) with BA and with PHV (r<0.83, p<0.05) in both sexes. MLP’s analysis revealed that the LM provides > 72% of probability to predict the muscle power of upper- and lower-limbs, and the strength of the upper limbs; whereas PHV provides > 43% and bone age >64% in both female and male adolescent athletes. Conclusion We identified that, like PHV and BA, LM is a strong predictor of low cost of both upper limbs muscle strength and upper and lower limbs power in adolescent athletes.

scholarly journals The Effectiveness of Biological Maturation and Lean Mass in Relation to Muscle Strength Performance in Elite Young Athletes

2020 ◽  
Vol 12 (17) ◽  
pp. 6696 ◽  
Author(s):  
Paulo Francisco de Almeida-Neto ◽  
Dihogo Gama de Matos ◽  
Adam D. G. Baxter-Jones ◽  
Gilmário Ricarte Batista ◽  
Vanessa Carla Monteiro Pinto ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Lean Mass ◽  
Lower Limb ◽  
Local Effect ◽  
Strength Development ◽  
Young Athletes ◽  
Cross Sectional ◽  
Strength Performance ◽  
Tennis Players ◽  
Lower Limb Strength

This study aimed to identify the interactional relationships between maturation (biological age (BA)) and lean mass on strength development in young athletes from different sports. Using a cross-sectional study design, a sample of 64 young athletes (rowers, swimmers, jiu-jitsu, volleyball, soccer and tennis players) of both sexes (13.6 ± 1.17 years) were recruited. Body composition was assessed using dual energy bone densitometry with X-ray source (DEXA). Strength of upper limbs (ULS), force hand grip (HG), vertical jump (VJ) and jump against movement (CMJ) were recorded. BA was estimated from anthropometrics. BA relationships were identified with upper limb strength in all athletes, and with the lower limb strength of tennis players, only (p < 0.05). An interaction effect between lean mass and BA was found (η2p = 0.753), as was a local effect within the regression models (ƒ2 ≥ 0.33). Athletes with a higher concentration of lean mass had superior upper and lower limb strength (p < 0.05). Lean mass showed a local effect (ƒ2) greater than that associated with BA. Although maturation is related to strength development, the strength of the relationship is mitigated by the accrual of lean mass. Specifically, the local effect of lean mass on muscle strength is broader than that of maturation, especially for lower limb strength.

scholarly journals Influence of skeletal maturation on physical fitness of young people with Down syndrome

2020 ◽  
Vol 34 (3) ◽  
pp. 373-383
Author(s):  
Everaldo Lambert Modesto ◽  
Leonardo dos Santos Oliveira ◽  
Bruna Barboza Seron ◽  
Eloise Werle de Almeida ◽  
Márcia Greguol
Keyword(s):  
Down Syndrome ◽  
Resistance Training ◽  
Muscle Strength ◽  
Young People ◽  
Physical Fitness ◽  
Intervention Program ◽  
Training Group ◽  
Lower Limbs ◽  
Skeletal Maturation ◽  
Control Group

Individuals with Down syndrome (DS) tend to prematurely reach the skeletal maturation period. In addition, young people with this condition have poor physical fitness and few opportunities to practice physical activity when compared to those without disabilities. The aim of this study was to investigate the skeletal maturation of young people with Down syndrome and its influence on the behavior of physical fitness related to health, after aerobic and resistance training programs. Forty people with DS, with an average age of 15.4 (± 2.6) years, were divided into three groups for a 12 weeks intervention program, AT - aerobic training group (3 times/week; 50 minutes/session), RT - resistance training group (twice/week ; 50 minutes/session) and CG - control group, 9 participants. Determination of skeletal age (EA) was performed using the Greulich-Pyle method. Anthropometric variables, muscle strength and peak VO2 were measured pre and post intervention. It was found that skeletal maturation influenced the effects of training, only being significant for body weight and strength in the upright row variables. In addition, the muscle strength of upper and lower limbs increased significantly after 12 weeks of aerobic or resistance training. Then, we can conclude that the effects of physical training on physical fitness of young people with Down syndrome appear to improve as the bone age increases.

Knee Flexor: Extensor Isokinetic Ratios in Young Male Gymnasts and Swimmers

2004 ◽  
Vol 16 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Theophanis Siatras ◽  
Dimitra Mameletzi ◽  
Spiros Kellis
Keyword(s):  
Young Male ◽  
Peak Torque ◽  
Antagonistic Activity ◽  
Lower Limbs ◽  
Training Context ◽  
Young Athletes ◽  
Isokinetic Testing ◽  
Angular Velocities ◽  
Muscle Groups ◽  
Isokinetic Peak Torque

The purpose of the study was to determine young male gymnasts’ and swimmers’ knee flexor:extensor (F:E) ratios during isokinetic testing at different velocities. Nine gymnasts (10.3 ± 0.5 years) and 14 swimmers (10.5 ± 0.5 years) participated. Concentric isokinetic peak torque was measured by a Cybex® Norm dynamometer at different angular velocities (60,120, and 180°/s) during unilateral knee extensions and flexions after gravity correction. Significant differences were found only in gymnasts’ knee F:E peak-torque ratios between the angular velocities of 60 and 120°/s (p < 0.01), as well as 60–180°/s (p < .01), whereas swimmers’ ratios were unchanged. Gymnasts presented significantly higher F:E ratios than swimmers did at the angular velocities of 120°/s (p < .01) and 180°/s (p < .001). The reciprocal ratios provided some indication that the training context of young athletes can influence the balance between agonistic and antagonistic activity of the lower limbs’ major muscle groups.

scholarly journals Unilateral and Bilateral Strength Asymmetry among Young Elite Athletes of Various Sports

Medicina ◽  
2020 ◽  
Vol 56 (12) ◽  
pp. 683
Author(s):  
Maros Kalata ◽  
Tomas Maly ◽  
Mikulas Hank ◽  
Jakub Michalek ◽  
David Bujnovsky ◽  
...  
Keyword(s):  
Lower Limb ◽  
Elite Athletes ◽  
Lower Limbs ◽  
Knee Extensors ◽  
Young Athletes ◽  
Lower Limb Muscles ◽  
Significant Difference ◽  
Strength Asymmetry ◽  
Main Factor ◽  
Objective Type

Background and objective: Type of physical activity may influence morphological and muscular asymmetries in the young population. However, less is known about the size of this effect when comparing various sports. The aim of this study was to identify the degree of bilateral asymmetry (BA) and the level of unilateral ratio (UR) between isokinetic strength of knee extensors (KE) and flexors (KF) among athletes of three different types of predominant locomotion in various sports (symmetric, asymmetric and hybrid). Material and methods: The analyzed group consisted of young elite athletes (n = 50). The maximum peak muscle torque of the KE and KF in both the dominant (DL) and non-dominant (NL) lower limb during concentric muscle contraction at an angular velocity of 60°·s−1 was measured with an isokinetic dynamometer. Results: Data analysis showed a significant effect of the main factor (the type of sport) on the level of monitored variables (p = 0.004). The type of sport revealed a significant difference in the bilateral ratio (p = 0.01). The group of symmetric and hybrid sports achieved lower values (p = 0.01) of BA in their lower limb muscles than those who played asymmetric sports. The hybrid sports group achieved higher UR values (p = 0.01) in both lower limbs. Conclusions: The results indicate that sports with predominantly symmetrical, asymmetrical, and hybrid types of locomotion affected the size of the BA, as well as the UR between KE and KF in both legs in young athletes. We recommend paying attention to regular KE and KF strength diagnostics in young athletes and optimizing individual compensatory exercises if a higher ratio of strength asymmetry is discovered.

Arthroscopic Imaging Treatment and Clinical Rehabilitation of Knee Sports Injuries

2021 ◽  
Vol 11 (6) ◽  
pp. 1780-1788
Author(s):  
Habaxi Kaken ◽  
Shanshan Wang ◽  
Wei Zhao ◽  
Baoerjiang Asihaer ◽  
Li Wang
Keyword(s):  
Muscle Strength ◽  
Knee Joint ◽  
Sports Injuries ◽  
Cruciate Ligament ◽  
Quadriceps Muscle ◽  
Lower Limbs ◽  
Continuous Passive Motion ◽  
Control Group ◽  
Pressure Therapy ◽  
Quick Recovery

This article studies the effects of arthroscopic imaging treatment and clinical rehabilitation of knee sports injuries. Arthroscopy was used to perform meniscus trimming and resection for 40 patients with knee sports injuries. The ages of the patients ranged from 20 to 60 years old. All patients received routine rehabilitation training such as continuous passive motion of the knee joint, biofeedback of the lower limbs, and air pressure therapy of the lower limbs. In addition, the control group was given muscle strength training, and the training began after the patients received the quadriceps muscle strength test. The removal of the joint cavity and the joint debridement has achieved satisfactory treatment results. In the experiment, the test cases were divided into two groups, and the sensor test platform was used for signal collection. Normal activities can be resumed 2 weeks after the operation. After a follow-up of 6 to 24 months, the knee joint pain disappeared, the joint was free of swelling, and the knee function was normal up to 93%. Arthroscopic reconstruction of the anterior and posterior cruciate ligament joint repair/reconstruction of the medial and posterolateral ligament knots is safe and feasible for the treatment of multiple ligament injuries of the knee joint. It has the advantages of less trauma and quick recovery. Early postoperative systemic and standardized rehabilitation exercises can obtain good knee joint function.

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