scholarly journals IMPACT OF COMPETITIVE LEVEL AND AGE ON THE STRENGTH AND ASYMMETRY OF YOUNG SOCCER PLAYERS

2018 ◽  
Vol 24 (5) ◽  
pp. 357-360 ◽  
Author(s):  
Jacielle Carolina Ferreira ◽  
Silvia Ribeiro Santos Araujo ◽  
Eduardo Mendonça Pimenta ◽  
Hans-Joachim Karl Menzel ◽  
Fabíola Bertú Medeiros ◽  
...  
Keyword(s):  
Peak Power ◽  
Muscular Strength ◽  
Reaction Force ◽  
Soccer Players ◽  
Diagnostic Study ◽  
Jump Height ◽  
Level Of Evidence ◽  
Strength Performance ◽  
Limb Asymmetry ◽  
Vertical Jumps

ABSTRACT Introduction: Muscular strength is an essential capacity for soccer players; however, the profile of this capacity has not yet been clearly established in young players. Objective: To compare muscular strength performance in the countermovement jump (CMJ) task and the presence of lower limb asymmetry among soccer athletes of the under 15 (U15), under 17 (U17) and under 20 (U20) categories, and between two teams of different competitive levels. Methods: One hundred and fifty one young soccer players of three different categories (U15, U17 and U20) from two teams in the Brazilian first and second divisions performed six vertical jumps in a system of two force plates. Ground reaction force (GRF) was used to calculate jump height and to obtain the variables Peak force (FMAX), Impulse (I) and Peak power (PMAX) with regard to body mass and the respective asymmetry values. Results: No differences were found in the performance and asymmetry variable between the categories (Jump height: p=0.23; FMAX: p=0.15; I: p=0.11; PMAX: p=0.32; FMAX asymmetry: p=0.21; I asymmetry: p=0.58; PMAX asymmetry: p=0.58). The first division club had higher muscle strength and asymmetry values than the second division club (Jump height: p<0.01; I: p<0.01; PMAX: p<0.01; FMAX asymmetry: p<0.01; I asymmetry: p<0.01; PMAX asymmetry: p<0.01), except for FMAX (p=0.63). No variable had an interaction effect (club x category). Conclusion: As categories progress, jump height, relative I, PMAX and FMAX values and their respective asymmetries are stable. The asymmetry and strength performance of the first division club were higher than that of the second division club, except for FMAX, indicating that the competitive level may influence strength performance and the development of asymmetry. Level of Evidence II; Diagnostic study – Investigating a diagnostic test.

Pelvic Kinematic Method for Determining Vertical Jump Height

2010 ◽  
Vol 26 (4) ◽  
pp. 508-511 ◽  
Author(s):  
Loren Z.F. Chiu ◽  
George J. Salem
Keyword(s):  
Vertical Jump ◽  
Center Of Mass ◽  
Reaction Force ◽  
Jump Height ◽  
Impulse Method ◽  
Vertical Jump Height ◽  
Reconstruction Methods ◽  
Kinematic Method ◽  
Mass Displacement ◽  
Vertical Jumps

Sacral marker and pelvis reconstruction methods have been proposed to approximate total body center of mass during relatively low intensity gait and hopping tasks, but not during a maximum effort vertical jumping task. In this study, center of mass displacement was calculated using the pelvic kinematic method and compared with center of mass displacement using the ground-reaction force-impulse method, in experienced athletes (n= 13) performing restricted countermovement vertical jumps. Maximal vertical jumps were performed in a biomechanics laboratory, with data collected using an 8-camera motion analysis system and two force platforms. The pelvis center of mass was reconstructed from retro-reflective markers placed on the pelvis. Jump height was determined from the peak height of the pelvis center of mass minus the standing height. Strong linear relationships were observed between the pelvic kinematic and impulse methods (R2= .86;p< .01). The pelvic kinematic method underestimated jump height versus the impulse method, however, the difference was small (CV = 4.34%). This investigation demonstrates concurrent validity for the pelvic kinematic method to determine vertical jump height.

scholarly journals Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Hadi Nobari ◽  
Jason M Cholewa ◽  
Alfonso Castillo-Rodríguez ◽  
Mehdi Kargarfard ◽  
Jorge Pérez-Gómez
Keyword(s):  
Peak Power ◽  
Muscular Strength ◽  
Soccer Players ◽  
Repeated Sprint Ability ◽  
Young Professional ◽  
Professional Soccer ◽  
Repeated Sprint ◽  
Competitive Season ◽  
Betaine Supplementation ◽  
Sprint Ability

Abstract Objective Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. Methods Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. Results Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. Conclusions 14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

scholarly journals PLYOMETRIC TRAINING IMPROVES SWIMMING PERFORMANCE IN RECREATIONALLY-TRAINED SWIMMERS

2020 ◽  
Vol 26 (5) ◽  
pp. 436-440
Author(s):  
Rodrigo Cañas-Jamett ◽  
Julio Figueroa-Puig ◽  
Rodrigo Ramirez-Campillo ◽  
Marcelo Tuesta
Keyword(s):  
Swimming Performance ◽  
Training Group ◽  
Control Group ◽  
Jump Height ◽  
Plyometric Training ◽  
Level Of Evidence ◽  
Squat Jump ◽  
Strength Performance ◽  
Swimming Time ◽  
Before And After

ABSTRACT Introduction: Plyometric training significantly improves strength performance, including in aquatic sports. Objective: To compare changes in thigh girth, hamstring flexibility, squat jump height, and 200m swimming trial time induced by plyometric training in recreationally-trained swimmers. Methods: Eighteen recreationally-trained male swimmers (age=18-20 years) were randomly divided into a plyometric training group (PTG) and a control group (CG). All the swimmers completed a six-week speed swimming training plan. In the PTG only, the last ~15 min of each session was replaced with plyometric exercises. The physical characteristics and the thigh girth were measured before and after the six weeks of training. In addition, sit-and-reach flexibility and squat jump tests were conducted, as well as a 200m swimming trial. Results: Two-way ANOVA with post-hoc analysis revealed an increase in sit-and-reach flexibility (PRE: 4.5±5.3 cm; POST: 10.9±5.9 cm, p<0.01) and squat jump height (PRE: 24.9±3.7 cm; POST: 28.3±4.2 cm, p<0.01) and a decrease in 200m-swimming time (PRE: 220±26.5 sec; POST: 204±24.4 sec, p<0.01) for the PTG only. Comparing the absolute changes (post-pre) between the groups by the Student's t-test, the PTG showed a greater increase in distance reached in the sit-and-reach flexibility (PTG: 6.34±0.6 cm vs. CG: 2.4±1.2 cm, p<0.01) and squat jump height (PTG: 3.4±0.7 cm vs. CG: 0.7±0.3 cm, p<0.01) than the CG. In addition, the 200m swimming time decreased significantly more than in the CG (PTG: -15.1±2.4 sec vs. CG: -0.8±2.7 sec, p<0.01). Conclusion: Plyometric training improves jump height, flexibility, and 200m swimming performance in recreationally-trained adult swimmers. Level of Evidence II; Lesser quality RCT.

The effects of vertically oriented resistance training on golf drive performance in collegiate golfers

2017 ◽  
Vol 13 (4) ◽  
pp. 598-606 ◽  
Author(s):  
Austin R Driggers ◽  
Kimitake Sato
Keyword(s):  
Resistance Training ◽  
Peak Power ◽  
Driving Performance ◽  
Peak Force ◽  
Division I ◽  
Jump Height ◽  
Countermovement Jump ◽  
Ball Speed ◽  
Force Development ◽  
Vertical Jumps

The purpose of this study was to examine the effects of vertically oriented resistance training on golf driving performance. Ten Division-I collegiate golfers completed two resistance training sessions per week for 10 weeks during the fall tournament season. Pre- and post-training assessments of strength-power and golf performance were compared. To assess strength-power, jump height, peak force, and peak power were measured from static and countermovement vertical jumps; peak force and rate of force development from 0 to 250 ms were measured from an isometric mid-thigh pull. Golf performance was assessed in terms of ball launch speed, spin rate, carry yardage, and total yardage, averaged from five shots using a driver. Following training, all measures of strength-power improved, with countermovement jump peak power improving significantly ( p < 0.00625). The golf performance assessment indicated significant increases ( p < 0.0125) in ball speed, carry yardage, and total yardage. These results suggest that vertically oriented resistance training can improve golf driving performance.

scholarly journals Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial

2021 ◽  
Author(s):  
Hadi Nobari ◽  
Jason M Cholewa ◽  
Alfonso Castillo-Rodríguez ◽  
Mehdi Kargarfard ◽  
Jorge Pérez-Gómez
Keyword(s):  
Peak Power ◽  
Muscular Strength ◽  
Controlled Trial ◽  
Soccer Players ◽  
Repeated Sprint Ability ◽  
Professional Soccer ◽  
Repeated Sprint ◽  
Competitive Season ◽  
Betaine Supplementation ◽  
Sprint Ability

Abstract Objective Various nutritional strategies are adopted for athletes to maintain and improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young soccer players. Methods Twenty-nine professional young soccer players (age, 15.5 ± 0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n = 14) or placebo (PG n = 15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction (modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30 − 15 intermittent fitness test) were assessed in the pre (P1), mid (P2), and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. Results Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. Conclusion 14-week of betaine supplementation increased 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and maintain performance during a competitive soccer season.

scholarly journals Effect of 6 Weeks of Preseason Concurrent Muscular Strength and Plyometric Training in Professional Soccer Players

2014 ◽  
Vol 48 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Shweta Shenoy ◽  
Amrinder Singh ◽  
Kartik Kulkarni ◽  
Jaspal Sandhu
Keyword(s):  
Muscular Strength ◽  
Vertical Jump ◽  
High Load ◽  
Soccer Players ◽  
Jump Height ◽  
Plyometric Training ◽  
Recovery Test ◽  
Professional Soccer ◽  
Vertical Jump Height ◽  
Soccer Training

ABSTRACT The purpose of this study was to compare the effects of combined strength and plyometric training with soccer training alone on strength and power-related measurements in professional soccer players. Subjects were randomly divided into two groups: group EG (n = 14) performed heavy resistance and plyometric training thrice a week during 6 weeks training period in addition to 6-8 soccer sessions per week; group CG (n = 14) performed 6-8 soccer sessions a week. EG significantly increased (p < 0.05) ball shooting speed and agility but showed no changes in body mass. Within-subject improvement was significantly higher (p < 0.01) in the EG compared with the CG for vertical jump height, 10 and 30 m sprint times, distances covered in the Yo-Yo intermittent recovery test. Plyometric can be concurrently performed with high load muscular strength training to enhance soccer players’ explosive performances. How to cite this article Singh A, Kulkarni K, Shenoy S, Sandhu J. Effect of 6 Weeks of Preseason Concurrent Muscular Strength and Plyometric Training in Professional Soccer Players. J Postgrad Med Edu Res 2014;48(1):27-32.

scholarly journals Ankle Orthosis-induced Decrease in Repetitive Rebound Jump Height: Relationship With Restriction in Sagittal Ankle Range of Motion

2021 ◽  
Author(s):  
Morikawa Masanori ◽  
Maeda Noriaki ◽  
Komiya Makoto ◽  
Kobayashi Toshiki ◽  
Urabe Yukio
Keyword(s):  
Range Of Motion ◽  
Athletic Performance ◽  
Contact Time ◽  
Peak Power ◽  
Vertical Jump ◽  
Reaction Force ◽  
Jump Height ◽  
Vertical Ground Reaction Force ◽  
Vertical Jump Height ◽  
Vertical Ground

Abstract Background: Ankle orthotics decreases the maximal vertical jump height. It is essential to maximize jump height and minimize ground contact time during athletic performance. However, the effect of ankle orthotics on athletic performance has not been reported. We aimed to investigate the effect of ankle orthotics on squat jump (SJ), countermovement jump (CMJ), and repetitive rebound jump (RJ) performance and the relationship between jump performance and restriction in sagittal ankle range of motion. Methods: Twenty healthy volunteers performed SJ, CMJ, repetitive RJ under no-orthosis and two orthotic conditions (orthosis 1 and orthosis 2). During SJ and CMJ, we measured the vertical ground reaction force and calculated the following parameters: jump height, peak vertical ground reaction force, rate of force development, net vertical impulse, and peak power. During repetitive RJ, the jump height, contact time, and RJ index were measured. A two-dimensional motion analysis was used to quantify the ankle range of motion in the sagittal plane during SJ, CMJ, and repetitive RJ. Results: Multivariate analysis of variance and the post hoc test showed a significant decrease in the vertical jump height (p = 0.003), peak power (p = 0.007), and maximum plantarflexion and dorsiflexion angles (p <0.001) during SJ using orthosis 2 compared to those using the no-orthosis condition. Additionally, orthosis 2 significantly decreased the jump height at the end of repetitive RJ (p = 0.046), during which a significant negative correlation was found between jump height and maximum dorsiflexion angle (r = 0.485, p = 0.030). Conclusions: An ankle orthosis-induced restriction of dorsiflexion is associated with a reduction in jump height during static jump and repetitive RJ performance.

scholarly journals Seasonal Changes and Relationships in Training Loads, Neuromuscular Performance, and Recovery and Stress State in Competitive Female Soccer Players

2021 ◽  
Vol 3 ◽  
Author(s):  
Ai Ishida ◽  
Caleb D. Bazyler ◽  
Adam L. Sayers ◽  
Michael H. Stone ◽  
Jeremy A. Gentles
Keyword(s):  
Stress State ◽  
Polyvinyl Chloride ◽  
Seasonal Changes ◽  
High Speed ◽  
Peak Power ◽  
Soccer Players ◽  
Jump Height ◽  
Neuromuscular Performance ◽  
Total Distance ◽  
Positive Correlations

Background: The purpose of this study was to examine seasonal changes in training load (TL), neuromuscular performance, subjective recovery, and stress state, and to investigate the relationships between acute and chronic TL and neuromuscular performance in competitive female soccer players.Methods: Nine competitive female soccer players (20.0 ± 1.7 years; 60.3 ± 6.3 kg; 164.0 ± 5.8 cm) completed the Short Recovery and Stress Scale and the countermovement jump (CMJ) with polyvinyl chloride pipe (CMJ0) and 20 kg barbell (CMJ20) at 2–3 h before 1st match (NC1), 6th match (NC2), 9th match (C1), and 15th match (C2) of the competitive season. TL included total distance, high-speed running, and PlayerLoad. Acute and chronic TL was calculated by using the average of 2 days (D2), 7 days (D7), and 21 days (D21) prior to four different match play.Results: Significant decreases were found from NC1 to C1 in D7 total distance [p = 0.03, Cohen's effect size (dz) = 1.40]. D7 total distance and PlayerLoad significantly decreased from NC to C1 and C2 (p = 0.001–0.01, dz = 1.40–1.72). Significant increases were observed from NC1 to C1 in CMJ0 jump height (p = 0.03, dz = 1.40), (p = 0.021, dz = 1.44), and peak power (p = 0.03, dz = 1.32). Significant negative correlations were observed for D7 total distance and CMJ0 jump height (p = 0.02, r = 0.79) and peak power (p = 0.03, r = 0.71) at C2, while significant positive correlations were observed at C1 for D7 PlayerLoad and CMJ0 jump height (p = 0.02, r = 0.80).Conclusion: Polyvinyl chloride pipe (CMJ0) jump height and peak power may increase from preseason to the midcompetitive season. Seasonal variations may affect the relationships between D7 TL and CMJ0 performance.

scholarly journals EFFECTS OF WEARING AN ANKLE BRACE ON GROUND REACTION FORCES DURING JUMPS IN BASKETBALL GAME SIMULATION

2021 ◽  
Vol 27 (2) ◽  
pp. 218-224
Author(s):  
Alex Castro ◽  
Márcio Fagundes Goethel ◽  
Edgar Ramos Vieira ◽  
Pedro Vieira Sarmet Moreira ◽  
Antônio Francisco de Almeida Neto ◽  
...  
Keyword(s):  
Loading Rate ◽  
Reaction Force ◽  
The Body ◽  
Ankle Injuries ◽  
Exercise Protocol ◽  
Basketball Players ◽  
Level Of Evidence ◽  
Basketball Game ◽  
Ankle Brace ◽  
Vertical Jumps

ABSTRACT Introduction: The use of ankle braces reduces the risk of ankle injuries in basketball players. However, the mechanisms of injury protection provided by the ankle braces in the basketball game are still unknown. Objectives: To analyze the effects of wearing a lace-up ankle brace, and to conduct an exercise protocol that simulated the intensity of the basketball game on ground reaction force (GRF) during basketball-specific vertical jumps. Methods: Eleven male younger basketball players aged under 18 completed 48 vertical jumps, with and without ankle braces, during an exercise protocol composed of four 10-minute periods, simulating the activity profile and intensity of the basketball game as well as the typical intervals between periods. Mediolateral (variables: the greatest medial and lateral peaks) and vertical (variables: vertical peak, impulse peak, impulse at 50 ms of landing, loading rate and jump height) GRF were measured during takeoff and landing for all the jumps performed in the exercise protocol. Results: The use of the ankle brace reduced mediolateral GRF in all periods of the exercise protocol during takeoff and landing ( P < 0.05), without affecting the vertical GRF ( P > 0.05). Mediolateral and vertical GRF (takeoff mediolateral vertical peaks, landing mediolateral peaks, landing impulse peak, takeoff and landing loading rate) increased significantly during four subsequent 10-minute periods ( P < 0.05). However, for mediolateral GRF, the increase overtime was higher without braces. Conclusions: The use of the ankle brace reduced the mediolateral GRF on the lower limb, while there was a progressive increase in the external load applied to the body during the vertical jumps in the subsequent periods of the exercise protocol performed at the same intensity of the basketball game. Level of evidence I; Randomized clinical trial .

scholarly journals Deferring Routine Wrist Radiography Does Not Affect Management of de Quervain Tendinopathy Patients

2017 ◽  
Vol 07 (02) ◽  
pp. 115-120 ◽  
Author(s):  
Tiffany Liu ◽  
Chia Wu ◽  
David Steinberg ◽  
David Bozentka ◽  
L. Levin ◽  
...  
Keyword(s):  
Physical Examination ◽  
Medical Center ◽  
Academic Medical Center ◽  
Diagnostic Study ◽  
Level Of Evidence ◽  
Radiographic Findings ◽  
Academic Medical ◽  
De Quervain ◽  
Clinical Records ◽  
Surgical Release

Background Obtaining wrist radiographs prior to surgeon evaluation may be wasteful for patients ultimately diagnosed with de Quervain tendinopathy (DQT). Questions/Purpose Our primary question was whether radiographs directly influence treatment of patients presenting with DQT. A secondary question was whether radiographs influence the frequency of injection and surgical release between cohorts with and without radiographs evaluated within the same practice. Patients and Methods Patients diagnosed with DQT by fellowship-trained hand surgeons at an urban academic medical center were identified retrospectively. Basic demographics and radiographic findings were tabulated. Clinical records were studied to determine whether radiographic findings corroborated history or physical examination findings, and whether management was directly influenced by radiographic findings. Frequencies of treatment with injection and surgery were separately tabulated and compared between cohorts with and without radiographs. Results We included 181 patients (189 wrists), with no differences in demographics between the 58% (110 wrists) with and 42% (79 wrists) without radiographs. Fifty (45%) of imaged wrists demonstrated one or more abnormalities; however, even for the 13 (12%) with corroborating history and physical examination findings, wrist radiography did not directly influence a change in management for any patient in this series. No difference was observed in rates of injection or surgical release either upon initial presentation, or at most recent documented follow-up, between those with and without radiographs. No differences in frequency, types, or total number of additional simultaneous surgical procedures were observed for those treated surgically. Conclusion Wrist radiography does not influence management of patients presenting DQT. Level of Evidence This is a level III, diagnostic study.

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