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1.
J Sport Rehabil ; : 1-6, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38936805

RESUMO

CONTEXT: The Hip Stability Isometric Test (HipSIT) is commonly employed in clinical settings for evaluating the hip posterolateral muscle strength. In this study, we introduced the "Field Hip Stability Isometric Test" (F-HipSIT) and assessed the intrarater and interrater reliability of this strength assessment specifically designed for sports settings. DESIGN: Reliability study. METHODS: Two independent raters (A and B) went to athletes' training facilities to conduct 2 sessions of F-HipSIT spaced at least 1 week apart. The average peak force value from 3 valid attempts of each leg was recorded and normalized by the participant's body mass for statistical analysis. RESULTS: Thirty male and 30 female amateur athletes took part in this study. Rater A obtained similar values in the first (0.39 [0.05] and 0.44 [0.07] kg·f/kg) and second (0.39 [0.06] and 0.45 [0.07] kg·f/kg) testing days for men and women, respectively. Rater B also found similar values in the first (0.35 [0.06] and 0.42 [0.08] kg·f/kg) and second (0.36 [0.06] and 0.45 [0.08] kg·f/kg) testing days for men and women, respectively. Excellent intrarater intraclass correlation coefficient (ICC) values were found for men (ICC = .922) and women (ICC = .930), with coefficient of variation of 6% to 8% and minimal detectable change of 0.06 to 0.10 kg·f/kg. The F-HipSIT presented good interrater reliability for men (ICC = .857) and women (ICC = .868), with coefficient of variation of 5% and minimal detectable change of 0.05 to 0.06 kg·f/kg. CONCLUSION: The F-HipSIT intrarater and interrater reliability among male and female recreational athletes supports this field test as a quick and convenient screening tool to monitor hip posterolateral muscle strength in sports settings.

2.
Phys Sportsmed ; : 1-6, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38651766

RESUMO

OBJECTIVE: To investigate the association of a novel post-match muscle pain map, named Muscle Pain Code (MPC), with the risk of subsequent time-loss muscle injury in a cohort of professional football (soccer) players. METHODS: The MPC classifies pain in four codes: code 0, 'no pain;' code 1, 'generalized muscle pain;' code 2, 'diffused site muscle pain;' and code 3, 'specific site muscle pain.' Over four consecutive seasons, MPC was collected on the second post-match day and players were followed for occurrence of time-loss muscle injury over the next five days. Players exposed to at least 45 minutes in two consecutive matches within seven days were included as cases for analysis. RESULTS: Eighty players participated in the study. Of 1,656 cases analyzed, 229 resulted in time-loss muscle injuries. Only 2% of cases with codes 0 and 1 resulted in time-loss muscle injuries. Conversely, 63% and 78% of codes 2 and 3 were followed by time-loss muscle injuries, respectively. Compared with the reference scenario (i.e. code 0 on MPC), the risk of subsequent time-loss muscle injury was significantly higher when players recorded code 2 (odds ratio, 4.29; 95%CI, 3.62 to 4.96) or code 3 (odds ratio, 5.01; 95%CI, 4.05 to 5.98) on MPC, but not when they recorded code 1 (odds ratio = -0.27; 95%CI, 1.05 to 0.56). CONCLUSIONS: Players experiencing well-outlined pain area on the second post-match day were more likely to incur a time-loss muscle injury in the subsequent days compared to those experiencing spreading pain or no pain.

3.
Phys Sportsmed ; : 1-6, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37548364

RESUMO

OBJECTIVE: The objective of this study was to examine the relationship between creatine kinase (CK) concentration following official matches and the risk of subsequent muscle injury in professional male football (soccer) players. METHODS: Blood samples were collected on the second post-match day for CK analysis over four consecutive seasons in a professional football club. Players were then followed for five days to observe any occurrence of indirect muscle injury (structural or functional in nature). Players exposed to at least 45 minutes in two consecutive matches within seven days were considered valid cases for analysis. RESULTS: Eighty players participated in the study, generating 1,656 cases eligible for analysis, of which 229 resulted in muscle injuries. The hamstrings were the most frequently injured muscle group (54%), followed by the adductor (21%), triceps surae (19%), quadriceps (5%), and psoas (1%). While CK concentration was higher in muscle injury cases [783 ± 507 U/L (95%CI, 717 to 849; min-max, 105-2,800)] compared with uninjured cases [688 ± 446 U/L (95%CI, 665 to 711; min-max, 100-2,950)], it was not an accurate predictor of subsequent muscle injury risk in professional football players (sensitivity = 56%; specificity = 55%; odds ratio = 1.00; area under curve = 0.557). CONCLUSION: CK concentration on the second post-match day cannot be used to effectively screen subsequent muscle injury risk in professional male football players.

4.
J Appl Biomech ; 39(2): 80-89, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36805932

RESUMO

Développé à la seconde is a classic ballet movement that requires the maintenance of a high hip joint range of motion (ROM) and muscle strength. However, the contribution of these hip joint biomechanical parameters to this movement's esthetic performance is unclear. Therefore, this study evaluated hip joint biomechanical characteristics of 21 experienced ballet dancers (15-29 y old) and verified the relationship between these variables with the développé à la seconde static and dynamic performance. Correlations between age, ballet practice time, gluteus maximus and gluteus medius thicknesses, ROM, and muscle strength with absolute and relative static and dynamic performances were verified. Flexors, extensors, and internal rotators peak strength and external rotation ROM were highly correlated with absolute and relative static performances (0.5-0.7). Flexors and extensors strength and external and internal rotation ROM showed the highest correlations with the développé dynamic performance (0.49-0.67). Flexor strength and flexor and internal rotation ROM predicted 26% to 41% of this movement's static and dynamic performances. Thus, from a biomechanical perspective, clinical assessment of hip strength and ROM may be used to predict the quality of the ballet dancers' performance of the développé à la seconde and guide classical ballet training.


Assuntos
Dança , Humanos , Dança/fisiologia , Articulação do Quadril/fisiologia , Músculo Esquelético/fisiologia , Movimento , Amplitude de Movimento Articular/fisiologia , Desempenho Físico Funcional
5.
Int J Sports Phys Ther ; 17(4): 613-621, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35693869

RESUMO

Background: The single leg bridge test (SLBT) has been introduced in the sports context as a way of estimating hamstring muscle capacity for prevention and rehabilitation of hamstring strain injuries. Purpose: The primary aim was to examine the association between SLBT scores with concentric and eccentric knee flexor peak torques. Secondarily, this study aimed examine the association of between-limb asymmetries provided by SLBT and isokinetic tests. Study design: Cross-sectional study. Methods: One hundred male soccer players (20±3 years) performed the SLBT and the knee flexion-extension isokinetic dynamometry evaluation (60°/s) billaterally during a single visit. SLBT score (i.e., number of repetitions until failure) and concentric and eccentric knee flexor peak torques (normalized per body mass) were considered for analysis. For both SLBT and isokinetic dynamometry, between-limb asymmetry was calculated as the percentage difference between the left limb and the right limb. Associations were assessed through Pearson's correlation coefficient. Results: The mean SLBT score was 33.6±9.6 repetitions, concentric peak torque was 2.00±0.22 Nm/kg, and eccentric peak torque was 2.79±0.44 Nm/kg. Between-limb asymmetry was 0.4±9.6%, 1.08±8.5%, and 1.64±14.61% in SLBT, concentric, and eccentric tests, respectively. There was a poor association of SLBT score with concentric (p<0.001, r=0.275) and eccentric (p=0.002, r=0.215) peak torques. The SLBT between-limb asymmetry was poorly associated with asymmetry found in concentric peak torque asymmetry (p=0.033, r=0.213) and was not associated with eccentric peak torque asymmetry (p=0.539, r=0.062). Conclusion: The SLBT should not be used as a clinical tool to assess the maximum strength of hamstring muscles. Level of Evidence: Level 3.

6.
J Sport Rehabil ; 31(1): 115-119, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34030120

RESUMO

CONTEXT: Eccentric knee flexor strength assessments have a key role in both prevention and rehabilitation of hamstring strain injuries. OBJECTIVE: To verify the reliability of a clinical test for measuring eccentric knee flexor strength during the Nordic hamstring exercise using a commercially available handheld dynamometer. DESIGN: Reliability study. SETTING: Physical Therapy Laboratory, Federal University of Health Sciences of Porto Alegre (Brazil). PARTICIPANTS: Fifty male amateur athletes (soccer or rugby players; 24 [3] y). MAIN OUTCOME MEASURES: Eccentric knee flexor strength. RESULTS: When compared with a load cell-based device, the clinical test using a handheld dynamometer provided smaller force values (P < .05) with large effect sizes (.92-1.21), moderate intraclass correlation (.60-.62), typical error of 30 to 31 N, and coefficient of variation of 10% to 11%. Regarding the test-retest reproducibility (2 sessions separated by 1 week), the clinical test provided similar force values (P > .05) with only small effect sizes (.20-.27), moderate to good correlation (.67-.76), typical error of 23 to 24 N, and coefficient of variation of 9% to 10%. CONCLUSION: The clinical test with handheld dynamometer proposed by this study can be considered an affordable and relatively reliable tool for eccentric knee flexor strength assessment in the clinical setting, but results should not be directly compared with those provided by load cell-based devices.


Assuntos
Músculos Isquiossurais , Força Muscular , Humanos , Joelho , Masculino , Dinamômetro de Força Muscular , Reprodutibilidade dos Testes
7.
Sports Biomech ; : 1-11, 2021 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-34882067

RESUMO

The study aimed to verify how age, height, body mass and body mass index affects the eccentric knee flexor strength during the Nordic hamstring exercise (NHE) in male soccer players. Ten professional soccer clubs were included in this cross-sectional trial. Three hundred and eleven soccer players (192 from senior and 119 from under-20 teams) were assessed using a load-cell based device. Pearson's correlation tests were performed between peak force values (measured in Newtons) and age, height, body mass and body mass index. The individual-limb strength (n = 622 limbs) and the between-limb average strength (n = 322 players) presented no correlation with age (r = 0.12 for both) and height (r = 0.13; r = 0,15), and fair correlations with body mass (r = 0.37; r = 0,41) and body mass index (r = 0.40; r = 0,43). In conclusion, the male soccer players' eccentric knee flexor strength measured during the NHE execution is not affected by age or height. Body mass and body mass index play somewhat effect on strength, thus normalising absolute strength measures by body mass or body mass index can provide more accurate analysis in some contexts.

8.
Int J Sports Phys Ther ; 16(2): 459-467, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33842041

RESUMO

BACKGROUND: Training programs that include the Nordic hamstring exercise (NHE) have been shown to increase eccentric knee flexor strength and biceps femoris fascicle length in male athletes. However, the effect of NHE on female athletes remains unknown. PURPOSE: To investigate the collective and individual responses of professional female soccer players engaged in a preseason training program with the NHE regarding eccentric knee flexor strength and biceps femoris long head fascicle length. STUDY DESIGN: Quasi-experimental study. METHODS: Sixteen amateur female soccer players (without a NHE training routine) were evaluated 8-weeks apart to: (1) assess reliability of eccentric knee flexor strength and biceps femoris fascicle length measures; and (2) determine the typical error of measures that would be used to discriminate training responders and non-responders. The NHE training group had 17 professional female soccer players who performed an 8-week training program with the NHE during preseason. Within-group analysis was performed with paired sample t-tests (pre- vs. post-training), and individual responses were determined using the typical error criteria. RESULTS: The non-trained group's data demonstrated that measures of strength (ICC=0.82-0.87, typical error = 12-13 N) and fascicle length (ICC=0.92-0.97; typical error = 0.19-0.38 cm) were reliable. In the NHE training group, both limbs increased the eccentric knee flexor strength (~13%; ES=0.74-0.82) and the biceps femoris fascicle length (~6%; ES=0.44-0.65). Twelve players (~71%) were considered responders to the NHE training program for the eccentric knee flexor strength, while eight athletes (~47%) were responders for the biceps femoris fascicle length. CONCLUSION: The 8-week preseason training program with the NHE increased both eccentric knee flexor strength and biceps femoris fascicle length in professional female soccer players. More than two-thirds of players demonstrated a meaningful increase in eccentric strength, while nearly half achieved consistent fascicle length increases with the NHE training.

9.
Eur J Sport Sci ; 21(1): 131-139, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32180535

RESUMO

Both injury history and eccentric knee flexor strength have been associated with risk of football players sustaining hamstring strain injury (HSI). However, it remains unclear whether football players who sustained HSIs in the prior season present persistent eccentric strength deficits. Therefore, the aim of the present study was to verify the eccentric knee flexor strength of professional male football players with and without history of HSI in the prior season. This case-control study assessed 210 professional male football players from 10 Brazilian clubs: 182 included in the control group and 28 in the previously injured group. Players from the injured group had suffered unilateral HSI in the prior season. We measured the knee flexors peak force during the Nordic hamstring exercise and calculated the between-limb asymmetry. Groups were similar for age, body mass and height (p > 0.05). Control group had similar strength values between left and right limbs (376.29 ± 61.77 N vs. 380.28 ± 61.77 N; p = 0.27; d = 0.06), while the previously injured limb was weaker than the contralateral uninjured limb in the injured group (350.87 ± 60.79 N vs. 385.75 ± 63.49 N; p < 0.01; d = 0.56). Thirty-seven percent of players in the control group and 50% in the injured group presented between-limb asymmetry >10%. This study demonstrates that players with history of HSI in the prior season present reduced eccentric knee flexor strength in the injured limb, but half of them have between-limb asymmetry within the most commonly adopted benchmark value of 10%.


Assuntos
Músculos Isquiossurais/lesões , Articulação do Joelho/fisiologia , Força Muscular/fisiologia , Futebol/lesões , Adulto , Brasil , Estudos de Casos e Controles , Músculos Isquiossurais/fisiopatologia , Humanos , Articulação do Joelho/fisiopatologia , Masculino , Estudos Retrospectivos , Estações do Ano , Futebol/fisiologia , Adulto Jovem
10.
Phys Ther Sport ; 47: 140-146, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33279801

RESUMO

OBJECTIVES: This study aimed at verifying the effect of a football match on the eccentric knee flexor strength of male professional players along a 72-h period. STUDY DESIGN: Quasi-experimental study. SETTING: Football club facilities. PARTICIPANTS: Fifteen players were assessed in four timepoints: 24 h before, immediately after, 48 h and 72 h after the match. MAIN OUTCOME MEASURES: The eccentric knee flexor strength was assessed during the Nordic hamstring exercise execution. RESULTS: Players presented a significant strength reduction immediately after match (Δ = 12%; p = 0.001; large effect size, d = 1.10), and did not recover their strength capacity within a 48 h-period (Δ = 6%; p = 0.011; moderate effect size, d = 0.57). At 72 h after the match, strength was similar to baseline levels (Δ = 3.5%; p = 0.122; small effect size, d = 0.34). Secondarily, individual response analysis considered a player 'fully recovered' when his strength deficit compared to the baseline measure was lower than the measurement coefficient of variation (i.e., <5%). Only 6 (40%) and 9 (60%) players were 'fully recovered' at 48 h and 72 h after the match, respectively. CONCLUSION: Professional football players experienced an immediately post-match drop on the eccentric knee flexor strength, and significant strength deficits persisted for a 48-h period. Some players were not recovered at 72 h after the match.


Assuntos
Comportamento Competitivo/fisiologia , Músculos Isquiossurais/fisiologia , Joelho/fisiologia , Força Muscular/fisiologia , Futebol/fisiologia , Adulto , Humanos , Masculino , Fatores de Tempo , Adulto Jovem
11.
Int J Sports Phys Ther ; 15(4): 571-578, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33354390

RESUMO

BACKGROUND: The Nordic hamstring exercise (NHE) is an effective strategy to prevent hamstring strain injuries in soccer players. The current literature recommends a 10-week training program with three sessions per week, but the short preseason period and the congested schedule make difficult for high-performance soccer teams to apply the NHE as recommended. PURPOSE: The purpose of this study was to examine the effect of a pragmatic NHE training program during a four-week preseason period on eccentric knee flexor strength of high-performance soccer players. STUDY DESIGN: Quasi-experimental clinical trial. METHODS: This study included 25 under-20 male soccer players from a premier league club. They performed eight sessions of NHE (3 sets of 6-10 repetitions, twice a week) during the four-week preseason period. The eccentric knee flexor strength was evaluated during the NHE execution on a custom-made device, before and after the training program. RESULTS: The NHE training program significantly increased the players' eccentric knee flexor strength in both right (Δ = 13%; p<0.001; effect size = 0.97) and left limbs (Δ = 13%; p<0.001; effect size = 0.92). Individual analysis identified 76% of the players as responders to the NHE training program (Δ = 16%; effect size = 1.60), and 24% as non-responders (Δ = 3%; effect size = 0.24). CONCLUSION: A four-week training program with NHE performed twice a week is feasible in the real-world of high-performance soccer clubs and increases the eccentric knee flexor strength of male soccer players.

12.
J Sport Rehabil ; 29(3): 339-345, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30747574

RESUMO

CONTEXT: Hamstring strain injury (HSI) is the most prevalent injury in football (soccer), and a few intrinsic factors have been associated with higher injury rates. OBJECTIVE: To describe the prevalence of the main intrinsic risk factors for HSI in professional and under-20 football players. DESIGN: Cross-sectional study. SETTING: Physiotherapy laboratory, Federal University of Health Sciences of Porto Alegre (Brazil). PARTICIPANTS: A total of 101 football players (52 professional and 49 under-20 players). INTERVENTION: An evidence-based testing protocol for screening HSI risk factors. MAIN OUTCOME MEASURES: Anamnesis, ultrasonography of the hamstrings, passive straight-leg raise test, Functional Movement Screen, and isokinetic dynamometry were performed. Eleven HSI risk factors for each leg were assessed, besides the player's age as a systemic risk factor. Reports were delivered to the coaching staff. RESULTS: Professionals had greater prevalence of HSI history compared with under-20 players (40% vs 18%). No between-group differences were found for the other screening tests. Altogether, 30% of players had already sustained at least one HSI; 58% had a history of injuries in adjacent regions; 49% had short biceps femoris fascicles; 66% and 21% had poor passive and active flexibility, respectively; 42% and 29% had deficits in functional movements and core stability, respectively; 7% and 26% presented bilateral imbalance for hamstring concentric and eccentric strength, respectively; 87% and 94% obtained low values for hamstring-to-quadriceps conventional and functional ratios, respectively. Two-thirds of players had 3 to 5 risk factors per leg. None of the players was fully free of HSI risk factors. CONCLUSION: Most football players present multiple risk factors for sustaining an HSI. Hamstring weakness is the most prevalent risk factor, but the teams should also be aware of deficits in flexibility, core stability, functional movements, and hamstring fascicle length.


Assuntos
Traumatismos em Atletas/epidemiologia , Músculos Isquiossurais/lesões , Programas de Rastreamento/métodos , Futebol/lesões , Entorses e Distensões/epidemiologia , Adolescente , Adulto , Traumatismos em Atletas/diagnóstico por imagem , Traumatismos em Atletas/fisiopatologia , Estudos Transversais , Teste de Esforço , Músculos Isquiossurais/diagnóstico por imagem , Músculos Isquiossurais/fisiopatologia , Humanos , Masculino , Força Muscular/fisiologia , Prevalência , Fatores de Risco , Entorses e Distensões/diagnóstico por imagem , Entorses e Distensões/fisiopatologia , Ultrassonografia , Adulto Jovem
13.
J Strength Cond Res ; 34(1): 281-293, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29794893

RESUMO

Baroni, BM, Ruas, CV, Ribeiro-Alvares, JB, and Pinto, RS. Hamstring-to-quadriceps torque ratios of professional male soccer players: A systematic review. J Strength Cond Res 34(1): 281-293, 2020-The goal of this review was to determine the isokinetic hamstring-to-quadriceps (H/Q) torque ratios of professional male soccer players. Systematic searches were independently carried out by 2 researchers in 7 electronic databases. Only studies with teams from the first or second national leagues were included. From these studies, we extracted the players' H/Q conventional (concentric/concentric) and/or functional (eccentric/concentric) ratios. The initial search resulted in 2,128 articles that were filtered to 30 articles (1,727 players) meeting the inclusion criteria. The H/Q conventional ratio was assessed in 27 studies (1,274 players), whereas the H/Q functional ratio was assessed in 15 studies (1,082 players). The H/Q conventional ratio mean scores of professional male soccer players were close to 60% when tested at low to intermediate angular velocities (12°·s = 52 ± 7%; 30°·s = 52 ± 8%; 60°·s = 65 ± 12%; 90°·s = 57 ± 6%; 120°·s = 65 ± 16%; 180°·s = 67 ± 17%) and around 70-80% at fast angular velocities (240°·s = 80 ± 40%; 300°·s = 70 ± 15%; 360°·s = 80 ± 13%). The H/Q functional ratio mean scores of professional male soccer players were close to 80% at 60°·s (79 ± 19%), around 100-130% at intermediate to fast angular velocities (120°·s = 127 ± 42%; 180°·s = 96 ± 19%; 240°·s = 109 ± 22%; 300°·s = 123 ± 18%), and near or above 130% when angular testing velocities were mixed (eccentric hamstring < concentric quadriceps; 30/240°·s = 132 ± 26%; 60/180°·s = 129 ± 20%; 60/240°·s = 153 ± 30%). In conclusion, considering the tested isokinetic angular velocity, professional male soccer players do not meet the traditional reference landmarks used to assess the strength balance between quadriceps and hamstring muscles (i.e., 60 and 100% for H/Q conventional and functional ratios, respectively), which supports a need for specific reference values according to the angular velocity selected for testing H/Q torque ratios.


Assuntos
Músculos Isquiossurais/fisiologia , Músculo Quadríceps/fisiologia , Futebol/fisiologia , Torque , Humanos , Masculino , Força Muscular , Valores de Referência
14.
Int J Sports Phys Ther ; 14(6): 877-884, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31803520

RESUMO

BACKGROUND: Poor flexibility is considered a risk factor for the hamstring strain injury, and the active straight leg raise (ASLR) test proposed as a part of the Functional Movement Screen™ (FMS™) has been used to assess athletes hamstring flexibility. However, the accuracy of this screening test remains undescribed. PURPOSE: To examine the accuracy of the FMS™ ASLR test for assessment of hamstring flexibility in soccer players. STUDY DESIGN: Cross-sectional study. METHODS: One-hundred and one male soccer players (age, 21 ± 3 years; height, 179 ± 7 cm; weight, 75 ± 9 kg) were bilaterally evaluated. All players performed a gold standard test for hamstring flexibility evaluation: the passive straight leg raise (PSLR) test measured using a gravitational inclinometer. All players also performed the ASLR test and were scored using the criteria proposed by the FMS™. RESULTS: Of the 202 lower limbs evaluated, 17.82% scored a 1 on the ASLR [mean passive flexibility: 80.44 ± 14.69 ° (55 °-110 °)], 50.99% scored a 2 on the ASLR [mean passive flexibility = 84.60 ± 10.59 ° (56 °-115 °)], and 31.18% scored a 3 on the ASLR [mean passive flexibility = 92.32 ± 11.53 ° (70 °-120 °)]. Limbs with FMS™ score of 3 presented significantly higher values for passive flexibility than limbs with scores of 1 and 2 (p < 0.05), but there was no significant difference between limbs with scores of 1 and 2 (p > 0.05). CONCLUSION: The score obtained in the FMS™ ASLR test does not satisfactorily stratify the level of hamstring flexibility in soccer players. LEVEL OF EVIDENCE: 3a.

15.
J Strength Cond Res ; 32(5): 1254-1262, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-28459795

RESUMO

Ribeiro-Alvares, JB, Marques, VB, Vaz, MA, and Baroni, BM. Four weeks of Nordic hamstring exercise reduce muscle injury risk factors in young adults. J Strength Cond Res 32(5): 1254-1262, 2018-The Nordic hamstring exercise (NHE) is a field-based exercise designed for knee-flexor eccentric strengthening, aimed at prevention of muscle strains. However, possible effects of NHE programs on other hamstring injury risk factors remain unclear. The purpose of this study was to investigate the effects of a NHE training program on multiple hamstring injury risk factors. Twenty physically active young adults were allocated into 2 equal-sized groups: control group (CG) and training group (TG). The TG was engaged in a 4-week NHE program, twice a week, 3 sets of 6-10 repetitions; while CG received no exercise intervention. The knee flexor and extensor strength were assessed through isokinetic dynamometry, the biceps femoris long head muscle architecture through ultrasound images, and the hamstring flexibility through sit-and-reach test. The results showed that CG subjects had no significant change in any outcome. TG presented higher percent changes than CG for hamstring isometric peak torque (9%; effect size [ES] = 0.27), eccentric peak torque (13%; ES = 0.60), eccentric work (18%; ES = 0.86), and functional hamstring-to-quadriceps torque ratio (13%; ES = 0.80). The NHE program led also to increased fascicle length (22%; ES = 2.77) and reduced pennation angle (-17%; ES = 1.27) in biceps femoris long head of the TG, without significant changes on muscle thickness. In conclusion, a short-term NHE training program (4 weeks; 8 training sessions) counteracts multiple hamstring injury risk factors in physically active young adults.


Assuntos
Exercício Físico/fisiologia , Músculos Isquiossurais/fisiologia , Articulação do Joelho/fisiologia , Traumatismos da Perna/prevenção & controle , Lesões dos Tecidos Moles/prevenção & controle , Adolescente , Adulto , Feminino , Humanos , Masculino , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Fatores de Risco , Torque , Adulto Jovem
16.
Phys Ther Sport ; 16(1): 59-65, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24913915

RESUMO

OBJECTIVES: To assess the inter-machine reliability of the Biodex System 3 Pro and Cybex Humac Norm Model 770 dynamometers for knee extensor and knee flexor peak torque measurements in isometric, concentric and eccentric tests. DESIGN: Randomized/crossover. SETTING: Exercise Research Laboratory, Federal University of Rio Grande do Sul (Brazil). PARTICIPANTS: 25 healthy male subjects. MAIN OUTCOME MEASURES: Isometric, concentric and eccentric knee extensor and knee flexor peak torques recorded in the same test procedure performed on both isokinetic dynamometers. One-way ANOVA, intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of variation (CV) were used to verify significant differences, relative and absolute reliability between devices. RESULTS: No significant differences were found between tests performed on Biodex and Cybex (p > 0.05). ICC values indicated a high to very high reproducibility for isometric, concentric and eccentric peak torques (0.88-0.92), and moderate to high reliability for agonist-antagonist strength ratios (0.62-0.73). Peak torque did not show great difference between dynamometers for SEM (3.72-11.27 Nm) and CV (5.27-7.77%). Strength ratios presented CV values of 8.57-10.72%. CONCLUSION: Maximal knee extensor and knee flexor tests performed in isometric (60° of knee flexion), concentric and eccentric modes at 60°/s in Biodex and Cybex dynamometers present similar values.


Assuntos
Articulação do Joelho , Contração Muscular/fisiologia , Dinamômetro de Força Muscular/normas , Músculo Quadríceps/fisiologia , Adulto , Desenho de Equipamento , Teste de Esforço , Humanos , Masculino , Músculo Esquelético/fisiologia , Reprodutibilidade dos Testes , Adulto Jovem
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