scholarly journals Isokinetic dynamometry of knee flexors and extensors: comparative study among non-athletes, jumper athletes and runner athletes

2002 ◽  
Vol 57 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Cássio Marinho Siqueira ◽  
Fábio Ribeiro Mendes Mota Pelegrini ◽  
Maurício Furginelli Fontana ◽  
Julia Maria D. Greve

Participation in intensive sports activities leads to muscular specializations that may generate alterations in involved articular forces and cause static (posture) and dynamic changes (alterations of articular stability, coordination, etc.). Prevention of injury requires specific functional muscular evaluation in all athletes and for any kind of sport. OBJECTIVE: To dynamically evaluate, through isokinetic tests, the peak torque, total work, and average power of the knee flexor and extensor muscles of jumper and runner athletes and compare them to those of a non-athletic population, evaluating dominance and balance between agonistic and antagonistic muscle groups. RESULTS: In the non-athlete group, we noted a higher asymmetry between the dominant and nondominant members. The jumpers had the highest values of the evaluated parameters of all groups, whereas parameters for the runners were intermediate between non-athletes and jumpers.

2019 ◽  
Vol 67 (1) ◽  
pp. 5-15 ◽  
Author(s):  
Amira Ben Moussa Zouita ◽  
Sghaier Zouita ◽  
Catherine Dziri ◽  
Matt Brughelli ◽  
David G. Behm ◽  
...  

AbstractInvestigations of trunk strength with high-level athletes are limited. The purpose of this study was to compare maximal concentric isokinetic trunk extension and flexion torque, power, and strength ratios between high-level weightlifters (n = 20), wrestlers (n = 20) and a control (n = 25) population. Isokinetic dynamometry was used to evaluate peak torque, power and strength ratios during seated trunk extension/flexion actions at 60°/s and 180°/s. There were no significant anthropometric differences between groups. Overall, trunk isokinetic force variables as a function of the increase in angular velocity, showed a decrease in peak torque, but an increase in power (athletes and controls). Compared to the control group, athletes demonstrated significantly higher trunk extension torque (+67.05 N·m, ES = 0.81) and power (+49.28 N·m, ES = 0.82) at 60°/s and 180°/s, respectively. Athletes produced significantly greater trunk flexion-extension ratios at 60°/s and 180°/s (ES = 0.80-0.47) than controls. Weightlifters and wrestlers exhibited significantly higher extensor than flexor torque at all angular velocities. Weightlifters demonstrated greater torque (ES = 0.79) than wrestlers at 60°/s. The wrestlers’ average power was significantly higher (ES = 0.43) than weightlifters at 180°/s. There were no significant ratio differences between wrestlers (66.23%) and weightlifters (72.06%). Weightlifters had stronger extensor muscles at 60°/s, whereas wrestlers had higher power at 180°/s for extensor muscles. It was postulated that the extensor muscles were stronger than the flexors to ensure trunk stabilisation, and for prevention of injuries. These differences seem to be associated to the movements that occur in each sport in terms of both muscle actions and contractile forces.


Retos ◽  
2015 ◽  
pp. 180-183
Author(s):  
James D. Burns ◽  
Paul C. Miller ◽  
Eric E. Hall

The focus of this research was to evaluate the effect whole body vibration (WBV) on measures of muscular contractile function. In addition, this research was conducted to compare the effects of WBV on athletes versus non-athletes. Nineteen male, non-athlete college students, as well as eighteen male Division I collegiate athletes participated in this research. All participants completed 2 conditions, vibration and no vibration, in a randomized order. Participants were exposed to either a 2-minute bout of vibration or a 2-minute no vibration condition. Immediately following both conditions, participants were tested for peak vertical jump height, isokinetic peak torque and average power of knee extensors and flexors, and anaerobic power during a 30-second maximal effort cycle task.  Results  showed  a  significant  improvement  in  knee  flexion peak torque at 6.28 rad·sec-1 in the athlete group following the vibration condition. Results also showed a trend toward a significant improvement in knee extensor and knee flexor average power at 6.28 radΧsec-1 in the athlete group following the vibration condition. There were no significant changes in any isokinetic measure for the non-athlete group. There were no significant changes in vertical jump or anaerobic power for either group. This may be due in part to the complexity of the dose-response relationship, which is largely dictated by the parameters of vibration frequency, amplitude, and duration. However, previous studies have found positive results using similar protocols as the present study. Practically speaking, the use of WBV prior to exercise may result in facilitated contractile and athletic performance. Consequently, this study sought to describe the impact of using WBV prior to exercise on muscle function.Key Words. Performance enhancement; Athletes; Power; Muscle Performance.Resumen. El objetivo de esta investigaciσn fue evaluar el efecto de la vibraciσn de cuerpo entero (WBV) sobre parαmetros de la funciσn contrαctil muscular. Ademαs, esta investigaciσn se realizσ para comparar los efectos de la WBV en atletas en comparaciσn con no atletas. Diecinueve hombres, estudiantes universitarios no deportistas, asν como 18 hombres, atletas de Divisiσn I universitaria participaron en esta investigaciσn. Todos los participantes completaron dos condiciones en orden aleatorio: la vibraciσn y la ausencia de vibraciσn. Los participantes fueron expuestos a 2 min de vibraciσn o una condiciσn de no vibraciσn por dos minutos. Inmediatamente despuιs de ambas condiciones, a los participantes se les midiσ la altura pico de salto vertical, el torque pico isocinιtico, la potencia media de extensores y flexores de la rodilla y la potencia anaerσbica durante una tarea de ciclo de esfuerzo mαximo 30 s. Los resultados muestran una mejorνa significativa en el torque pico de la rodilla a 6.28 rad·sec-1 en el grupo de deportistas luego de la condiciσn de vibraciσn. Los resultados tambiιn muestran una tendencia hacia un aumento significativo en la potencia promedio de los flexores y extensores de la rodilla a 6.28 rad·sec-1 en el grupo de deportistas luego de la condiciσn de vibraciσn. No hubo cambios significativos en las variables isocinιticas en el grupo de no atletas. Tampoco hubo cambios significativos en el salto vertical ni en la potencia anaerσbica en ambos grupos. Esto puede explicarse en parte a la complejidad de la relaciσn de dosis-respuesta, la cual estα ampliamente determinada por los parαmetros de frecuencia, amplitud y duraciσn de la vibraciσn. Sin embargo, estudios previos han encontrado resultados positivos utilizando protocolos similares a los del presente estudio. En tιrminos prαcticos, el uso de WBV antes del ejercicio puede resultar en una mejor contractilidad y rendimiento deportivo. En consecuencia, este estudio tratσ de describir el impacto del uso de WBV antes del ejercicio en la funciσn muscular.Palabras claves. mejora del rendimiento, atletas, potencia, rendimiento muscular


1984 ◽  
Vol 57 (2) ◽  
pp. 435-443 ◽  
Author(s):  
T. L. Wickiewicz ◽  
R. R. Roy ◽  
P. L. Powell ◽  
J. J. Perrine ◽  
V. R. Edgerton

The in vivo torque-velocity relationships of the knee extensors (KE), knee flexors (KF), ankle plantarflexors (PF), and ankle dorsiflexors (DF) were determined in 12 untrained subjects using an isokinetic testing device (Cybex II). These data were then matched to the predicted maximum forces and shortening velocities derived from muscle architectural determinations made on three hemipelvectomies (36). The torque-velocity curves of all muscle groups resembled that predicted by Hill's (19, 20) equation except at the higher forces and lower velocities. The peak torques occurred at mean velocities ranging from 41–62 rad X s-1 for the KE, KF, and PF. Although the peak torque of the DF occurred at the isometric loading condition, it was also lower than that predicted by Hill's equation. The muscle fiber length and physiological cross-sectional area measurements indicate that the architecture of the human leg musculature has a major influence on the torque-velocity characteristics. These data corroborate previous findings (24) that some neural inhibitory mechanism exists in the control of the leg musculature, which limits the maximum forces that could be produced under optimal stimulating conditions.


2014 ◽  
Vol 20 (3) ◽  
pp. 310-316
Author(s):  
Gislaine Regina Santos dos Santos ◽  
Jeam Marcel Geremia ◽  
Paola Zambelli Moraes ◽  
Raquel de Oliveira Lupion ◽  
Marco Aurélio Vaz ◽  
...  

Asymmetric performance of flexor and extensor muscles of the knee may be a risk factor for knee injuries, especially the anterior cruciate ligament. Additionally, asymmetries in power and work may have correlations with fatigue and performance during functional tasks. Among untrained individuals, such asymmetries may be of potential interest for training prescription. Here, we investigated the bilateral performance of knee flexors and extensors muscle groups of untrained individuals. We quantified the torque-angle and torque-velocity relationships, as well as work, power and asymmetry indexes in 20 untrained male (25 ± 4 years old; height 1.74 ± 0.05 m; body mass 76 ± 9 kg). No significant asymmetry was observed for torque-angle and torque-velocity relationships, work and power output for knee flexor and extensor muscle groups (p < .05). Our results suggest that untrained male present symmetry in the knee flexion and extension bilateral performance. Changes in this behavior due to physical training must be monitored.


2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
P Oleinik ◽  
AN Sumin ◽  
AV Bezdenezhnykh

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Research Institute for Complex Issues of Cardiovascular Diseases Aim To evaluate the effects of neuromuscular electrostimulation in the prehabilitation and prevention of muscle weakness in patients awaiting cardiac surgery. Materials and methods 122 patients waiting for elective cardiac surgery were included. Exclusion criteria: age less than 25 and more than 80 years; emergency and urgent surgical interventions; arthropathies; low pain threshold; rhabdomyolysis and other myopathies; cognitive dysfunction. Routine laboratory and instrumental examinations were performed in all patients upon admission to the hospital, as part of a standard examination. 62 patients were randomly selected for the preoperative NMES group, in addition to the standard preoperative preparation and treatment program. The standard program included 60 control patients. Patients of the NMES group underwent quadriceps stimulation for at least 5 sessions, lasting 90 minutes, daily before surgery. Results. The groups were comparable and did not have significant differences in gender and age characteristics, according to the main clinical and anamnestic data and types of operations. Initially, there were no differences in the state of the muscles of the lower extremities, the distance of the six-minute walking test (6MWT), and the strength of the hand grip. After NMES, there was an increase in muscle strength relative to the control group, both stimulated muscle groups and unstimulated antagonist muscles, as well as a greater 6MWT distance and hand compression force. All the differences were significant. Conclusions The course of pre-rehabilitation of NMES before surgery, allowed to maintain, and in some cases improve the condition of the muscle frame of the lower extremities. A positive effect was observed not only in stimulated muscle groups, but also in antagonist muscles Indicators of muscle status NMES (n = 62) Control group (n = 60) Baseline Discharge Baseline Discharge P-level Right knee extensors strength (kg) 24,4 [18,3; 31,4] 30,4 [23,8; 36,2]* 24,7 [20,1; 33,2] 22,25 [18,9; 30,4] &lt;0,001 Left knee extensors strength (kg) 23,8 [19,3; 31,3] 29,2 [23,6; 35,4]* 25,75 [19,2; 31,3] 22,9 [18,9; 27,8] &lt;0,001 Right knee flexors strength (kg) 18,9 [13,3; 24,0] 21,7 [16,6; 25,1] 19,55 [13,1; 26,0] 16,7 [12,1; 23,3] 0,006 Left knee flexors strength (kg) 19,3 [14,3; 24,5] 21,9 [17,3; 26,7] 19,5 [13,0; 24,3] 18,2 [13,4; 22,2] 0,005 6-MWT (m) 300,0 [261,0; 371,0] 331,0 [280,0; 375,0] 304,5 [253,0; 380,0] 285,5 [246,0; 342,0] 0,006 Right handgrip strength (kg) 28,5 [20,5; 34,0] 31,5 [22,0; 34,0] 29,0 [19,0; 34,0] 27,0 [19,0; 33,0] 0,054 Left handgrip strength (kg) 25,0 [18,0; 31,0] 25,0 [18,0; 32,0] 24,0 [15,0; 31,0] 22,0 [14,0; 28,0] 0,062 * - p-level from baseline data &lt; 0,05 Abstract Figure. dynamics of stimulated muscles


Author(s):  
Wieslaw Blach ◽  
Miodrag Drapsin ◽  
Nemanja Lakicevic ◽  
Antonino Bianco ◽  
Tamara Gavrilovic ◽  
...  

Elite judo athletes undergo vigorous training to achieve outstanding results. In pursuit of achieving competitive success, the occurrence of injuries amongst judo athletes is not rare. The study aimed to perform a knee flexors and extensors isokinetic torque analysis in elite female judo athletes. Fifty-eight elite female judo athletes of the Serbian national team (21.02 ± 3.11 years; 62.36 ± 11.91 kg, 165.04 ± 10.24 cm, training experience 12.72 ± 2.98 years) volunteered to participate in this study. The range of motion (ROM) was set at 90⁰. Testing was performed in a concentric–concentric mode for the testing speed of 60 ⁰/s. Five maximal voluntary contractions of knee extensors and knee flexors muscle groups were measured for both legs. The obtained data showed a statistically significant difference in absolute torque values among different categories as heavier athletes demonstrated higher values. Post hoc analysis showed a significant difference between weight categories, as heavier athletes demonstrated higher values, while no significant differences in normalized torque values for different weight categories were observed. The implementation of new elements and training modalities may improve performance and prevent lateral asymmetry, thus reducing the risk of injury.


Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 397
Author(s):  
Mohamad Fashi ◽  
Sajad Ahmadizad ◽  
Hadi Nobari ◽  
Jorge Pérez-Gómez ◽  
Rafael Oliveira ◽  
...  

The aim of this study was to investigate the effect of acute Ramadan fasting (RF) on the muscle function and buffering system. Twelve male athletes with 8 years of professional sports experience (age, 23.2 ± 1.3 years, body mass index: 24.2 ± 2.2 kg/m2) participated in this study. The subjects were tested twice, 3 weeks after the beginning of RF and 2 weeks after the end RF. Muscle function, buffering capacity, and rating of perceived exertion (RPE) were measured during and after RF by using the Biodex isokinetic machine, blood gas analyzer, and RPE 6–20 Borg scale, respectively. Venous blood samples for pH and bicarbonate (HCO3−) were measured during and after RF by using the Biodex isokinetic machine, blood gas analyzer, and RPE 6–20 Borg scale, respectively. Venous blood samples for pH and bicarbonate (HCO3−) were taken immediately after 25 repetitions of isokinetic knee flexion and extension. Measures taken during isokinetic knee extension during RF were significantly lower than those after RF in extension peak torque (t = −4.72, p = 0.002), flexion peak torque (t = −3.80, p = 0.007), extension total work (t = −3.05, p = 0.019), extension average power (t = −4.20, p = 0.004), flexion average power (t = −3.37, p = 0.012), blood HCO3− (t = −2.02, p = 0.041), and RPE (Z = −1.69, p = 0.048). No influence of RF was found on the blood pH (t = 0.752, p = 0.476). RF has adverse effects on muscle function and buffering capacity in athletes. It seems that a low-carbohydrate substrate during RF impairs muscle performance and reduces the buffering capacity of the blood, leading to fatigue in athletes.


1983 ◽  
Vol 55 (1) ◽  
pp. 218-224 ◽  
Author(s):  
N. McCartney ◽  
G. J. Heigenhauser ◽  
N. L. Jones

We studied maximal torque-velocity relationships and fatigue during short-term maximal exercise on a constant velocity cycle ergometer in 13 healthy male subjects. Maximum torque showed an inverse linear relationship to crank velocity between 60 and 160 rpm, and a direct relationship to thigh muscle volume measured by computerized tomography. Peak torque per liter thigh muscle volume (PT, N X ml-1) was related to crank velocity (CV, rpm) in the following equation: PT = 61.7 - 0.234 CV (r = 0.99). Peak power output was a parabolic function of crank velocity in individual subjects, but maximal power output was achieved at varying crank velocities in different subjects. Fiber type distribution was measured in the two subjects showing the greatest differences and demonstrated that a high proportion of type II fibers may be one factor associated with a high crank velocity for maximal power output. The decline in average power during 30 s of maximal effort was least at 60 rpm (23.7 +/- 4.6% of initial maximal power) and greatest at 140 rpm (58.7 +/- 6.5%). At 60 rpm the decline in power over 30 s was inversely related to maximal oxygen uptake (ml X min-1 X kg-1) (r = 0.69). Total work performed and plasma lactate concentration 3 min after completion of 30-s maximum effort were similar for each crank velocity.


1996 ◽  
Vol 80 (1) ◽  
pp. 332-340 ◽  
Author(s):  
C. P. Ingalls ◽  
G. L. Warren ◽  
D. A. Lowe ◽  
D. B. Boorstein ◽  
R. B. Armstrong

The purpose of this study was to evaluate the effects of four anesthetic regimens on in vivo contractile function of mouse ankle dorsiflexor muscles. The torque-frequency and torque-velocity relationships were determined for the following anesthetics: fentanyl-droperidol and diazepam (F-d/d); ketamine and xylazine (K/x); pentobarbital sodium (Ps); and methoxyflurane (Mf). Mf, Ps, and F-d/d regimens resulted in comparable contractile responses at low doses, whereas K/x produced a relative depression in isometric contractile function as shown by a decrease in the torque-time integral at the 300-Hz stimulation frequency (-13.9%; P < 0.05). Moreover, K/x caused a shift to the left in the torque-frequency curve as indicated by increases in torque-time integrals at 25 and 50 Hz. Both Ps and F-d/d regimens exhibited dose-dependent effects during the isovelocity contractions. Ps significantly reduced work (-28.7%) and average power (-28.9%) at 800 degrees/s at the high dose. In contrast, F-d/d anesthesia resulted in increases in peak torque (16-20%) and work (15-18%) output at all eccentric contraction velocities at the high dose, whereas average power was increased only at -800 (17%) and -1,000 degrees/s (17%). In conclusion, commonly used anesthetic regimens can affect the contractile response in vivo; K/x and Ps yield smaller torque outputs, whereas Mf and F-d/d consistently produce larger contractile responses. Mf and F-d/d are recommended for use in studying skeletal muscle function in mice in vivo.


2017 ◽  
Vol 5 (3_suppl3) ◽  
pp. 2325967117S0010
Author(s):  
Kotaro Shibata ◽  
Marc R. Safran

Objectives: 1) To compare ability to return to prior competitive sports activity after arthroscopic hip surgery by gender, with an emphasis on the rate of return to the same level of competition. 2) To compare gender differences in type of sports activities, diagnosis and treatment in athletes requiring hip arthroscopy. Methods: Prospectively obtained data on all high-level elite athletes (professional, NCAA collegiate and/or Olympic) treated between 2007 and 2014 were retrospectively reviewed. The clinical and surgical records of 547 hips in 484 consecutive patients who underwent primary hip arthroscopy by the senior author for non-arthritic hip pain during the study period were included. Elite athletes who had a Hip Sports Activity Score (HSAS) of over 6 were identified. Patients completed a pre-operative questionnaire that included medical and sports activity history and level of competition, hip-specific outcome scores (Modified Harris Hip Score [MHHS] and International Hip Outcome Tool-33 [iHOT-33]) at baseline and most recent follow-up. Surgical findings and time to return to competitive sports activity were documented. Results: A total of 98 elite athletes with a mean follow up period of 18.8 months (±12.7) were identified. There were 49 females and 49 males. 27 athletes had bilateral hip arthroscopy, 5 of which had 1 operation elsewhere. All patients were available for follow up. Of the 80 patients desiring to return to their original competitive activity, 38 were female (42 hips) (Female Athlete group [FA]) and 42 were male (54 hips) (Male Athlete group [MA]) their mean ages were 21.5(±3.9) and 20.5(±1.9), duration of pain prior to surgery was 12.1 (±10.3) months and 15.1 (±1.9) months, respectively. 84.2% of FA and 83.3% of MA were able to return to the same level of competition at a mean of 8.3 (±3) and 8.8 (±2.9) months, respectively. Statistically significant improvements between pre- and post-operative mean MHHS and iHOT-33 scores were seen in both groups (p <.0001; p <.0001). FA had significantly higher proportions of hips that were diagnosed with Pincer type FAI (p =.0004), and Instability (p <.0001). Conversely, the MA had significantly higher proportions of hips that were diagnosed with Combined type FAI (p <.0001), had more extensive acetabular cartilage rim damage (p =.0002), and in particularly had more hips that required microfracture treatment (p =.001). When comparing cam lesions (includes Cam and Combined type FAI) the alpha angle was statistically greater in MA (mean 74°±6.7) compared to FA (mean 65.4°±6.8) (p <.0001). The category of sports the FA participated in were more flexibility (11%) and endurance (24%) type sports. MA participated more in cutting (33%), contact (14%) and asymmetric (31%) type sports. Patients who were able to return to same level of competitive activity had a significantly shorter duration of pre-operation symptoms compared to those who could not (p < 0.05). Microfracture treatment did not affect the ability to return to sports. Conclusion: A similar high percentage of both female and male elite athletes were able to return to competitive sports activity after arthroscopic treatment of FAI and/or hip instability. Distinct differences in diagnosis, treatment and participating type of sports activities were seen when comparing female and male athletes. Duration of symptoms negatively correlated with outcomes. Extensive cartilage damage and Microfracture did not affect outcome / return to sports.


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