scholarly journals A 12-Week Randomized Double-Blind Placebo-Controlled Clinical Trial, Evaluating the Effect of Supplementation with a Spinach Extract on Skeletal Muscle Fitness in Adults Older Than 50 Years of Age

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4373
Author(s):  
Silvia Pérez-Piñero ◽  
Vicente Ávila-Gandía ◽  
Jacobo A. Rubio Arias ◽  
Juan Carlos Muñoz-Carrillo ◽  
Pilar Losada-Zafrilla ◽  
...  
Keyword(s):  
Spinacia Oleracea ◽  
Peak Torque ◽  
Knee Extension ◽  
Muscle Quality ◽  
Moderate Intensity ◽  
Total Work ◽  
Double Blind ◽  
Repetition Maximum ◽  
Spinacia Oleracea L ◽  
Muscle Fitness

The aim of a 12-week randomized double-blind placebo-controlled study was to assess the effect of daily supplementation with a natural extract of Spinacia oleracea L. (4 × 500 mg capsules/day; total 2 g per day) combined with a moderate-intensity training program (1 h session/3 times a week) on skeletal muscle fitness in adults over 50 years of age. Muscle strength assessed by isokinetic and isometric dynamometry improved significantly in the experimental (n = 23) and the placebo (n = 22) groups, but the magnitude of improvement was higher in the experimental group, with between-group differences in almost all variables, including isokinetic at 60° s−1 in knee extension, peak torque (p < 0.007); total work per repetition maximum (p < 0.009); isokinetic at 180°s−1 in knee extension, peak torque (p < 0.002); total work (p < 0.007); total work per repetition maximum (p < 0.005); average power (p < 0.027); isometric in knee extension, peak torque (p < 0.005); and average peak torque (p < 0.002). Similar findings were observed for muscle quality. Changes in quality of life (SF-36) were not found, except for improvements in the role physical (p < 0.023) and role emotional (p < 0.001) domains, likely as a result of the physical training sessions. A nutritional survey did not revealed changes in dietary habits. No adverse events were recorded. In subjects over 50 years of age, moderate-intensity strength training combined with daily supplementation for 12 weeks with a natural extract of Spinacia oleracea L. improved muscle-related variables and muscle quality. Maintaining muscle health is a key component of healthy aging.

scholarly journals Isokinetic evaluation of knee muscles in soccer players: discriminant analysis

2015 ◽  
Vol 21 (5) ◽  
pp. 364-368 ◽  
Author(s):  
Bruno Fles Mazuquin ◽  
Ligia Maxwell Pereira ◽  
Josilainne Marcelino Dias ◽  
João Pedro Batista Junior ◽  
Mônica Angélica Cardoso Silva ◽  
...  
Keyword(s):  
Human Performance ◽  
Average Power ◽  
Peak Torque ◽  
Knee Extension ◽  
Soccer Players ◽  
Total Work ◽  
Wilks Lambda ◽  
Discriminant Analyses ◽  
Definition Of ◽  
Flexion And Extension

ABSTRACT Introduction: Muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: To perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional (PRO). Methods: Thirty four players were assessed (n=17 for each category). The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm), total work (J), average power (W), angle of peak torque (deg.), agonist/ antagonist ratio (%), measured for three velocities (60°/s, 120°/s and 300°/s), with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories. Results: The discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work. Conclusion: Isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players.

Age- and sex-associated differences in isokinetic knee muscle endurance between young children and adults

2009 ◽  
Vol 34 (4) ◽  
pp. 725-731 ◽  
Author(s):  
Mark B.A. De Ste Croix ◽  
Martine A. Deighan ◽  
Sebastien Ratel ◽  
Neil Armstrong
Keyword(s):  
Young Children ◽  
Peak Torque ◽  
Knee Extension ◽  
Total Work ◽  
Adult Males ◽  
Significant Interaction Effect ◽  
Peak Knee ◽  
Knee Muscle ◽  
Main Effects ◽  
Age And Sex

The purpose of this study was to examine the age- and sex-associated differences of repeated isokinetic knee extension and flexion. Fifty one participants, 30 young children (16 boys and 14 girls; aged 11 and 12 years) and 21 adults (9 males and 12 females; aged 18–35 years), agreed to participate in the study. Isokinetic concentric peak knee extension (PET) and flexion (PFT) torque were measured using a calibrated Biodex System 3. Participants performed 4 concentric extension–flexion cycles with maximum effort; after a 2 min rest, 50 continuous concentric cycles were performed at 1.56 rad·s–1. Total work of the extensors (WKEX) and flexors (WKFL) for the complete 50 repetitions was recorded. Average peak torque and average work for the first and last 3 repetitions were calculated to represent the percentage decline in torque and work. There were no significant differences between groups in the peak torque generated during the pretrial and endurance task, suggesting that participants gave a maximal effort at the start of the endurance task. There was a significant interaction effect in the total work done for both extensors and flexors, with adult males producing the greatest amount of work (6622 and 3444 J, respectively). When total work was divided by body mass, there were no significant sex effects, only main effects for group. The percentage decline for PET (40% vs. 60%), PFT (50% vs. 65%), WKET (43% vs. 61%), and WKFL (60% vs. 69%) demonstrated significant main effects for group, with greater fatigue in adults. We found no significant sex effect for fatigue. This study concludes that females do not resist fatigue from repeated isokinetic muscle actions to a greater extent than males, and that the greater fatigue in adults than in children is probably a product of greater initial torque production and work performed.

Effects of Hydraulic Resistance Strength Training on Isokinetic Measures of Leg Strength in Men with Mental Retardation

1995 ◽  
Vol 12 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Rory Suomi ◽  
Paul R. Surburg ◽  
Peter Lecius
Keyword(s):  
Mental Retardation ◽  
Hydraulic Resistance ◽  
Peak Torque ◽  
Knee Extension ◽  
The Other ◽  
Isokinetic Strength ◽  
Total Work ◽  
Trained Subjects ◽  
Leg Strength ◽  
Hip Abduction

The purpose of this study was to determine the effects of hydraulic resistance (HR) training on total work and peak torque measures of isokinetic strength for tests of knee extension and hip abduction on men with mental retardation (MR). The subjects, 22 men with mild to moderate MR, were randomly assigned to two groups; 11 subjects trained three times a week for 12 weeks using HR exercise machines, while the other 11 served as controls. Prior to and after the 12 weeks of training, all subjects were assessed on isokinetic tests of knee extension at 60 deg/s and hip abduction at 30 deg/s. The strength trained subjects exhibited significant increases in total work scores on knee extension and hip abduction tests for both legs ranging from 25.0 to 177.1%. Significant increases ranging from 50.1 to 82.7% were also noted on two of the four peak torque measures. The control subjects did not exhibit significant changes in total work or peak torque scores on either muscle test between test sessions.

Ability of Isokinetic Dynamometer to Predict Isotonic Knee Extension 1-Repetition Maximum

2020 ◽  
Vol 29 (5) ◽  
pp. 616-620
Author(s):  
Joseph B. Lesnak ◽  
Dillon T. Anderson ◽  
Brooke E. Farmer ◽  
Dimitrios Katsavelis ◽  
Terry L. Grindstaff
Keyword(s):  
Resistance Training ◽  
Knee Injury ◽  
Peak Torque ◽  
Knee Extension ◽  
Prediction Equation ◽  
Isokinetic Dynamometer ◽  
Physically Active ◽  
Repetition Maximum ◽  
Knee Rehabilitation ◽  
Torque Values

Context: Resistance training exercise prescription is often based on exercises performed at a percentage of a 1-repetition maximum (1RM). Following knee injury, there is no consensus when a patient can safely perform 1RM testing. Resistance training programs require the use of higher loads, and loads used in knee injury rehabilitation may be too low to elicit gains in strength and power. A maximum isometric contraction can safely be performed during early stages of knee rehabilitation and has potential to predict an isotonic knee extension 1RM. Objective: To determine whether a 1RM on an isotonic knee extension machine can be predicted from isometric peak torque measurements. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: A total of 20 (12 males and 8 females) healthy, physically active adults. Main Outcome Measures: An isokinetic dynamometer was used to determine isometric peak torque (in N·m). 1RM testing was performed on a knee extension machine. Linear regression was used to develop a prediction equation, and Bland–Altman plots with limits of agreement calculations were used to validate the equation. Results: There was a significant correlation (P < .001, r = .926) between peak torque (283.0 [22.6] N·m) and the knee extension 1RM (69.1 [22.6] kg). The prediction equation overestimated the loads (2.3 [9.1] kg; 95% confidence interval, −15.6 to 20.1 kg). Conclusions: The results show that isometric peak torque values obtained on an isokinetic dynamometer can be used to estimate 1RM values for isotonic knee extension. Although the prediction equation tends to overestimate loads, the relatively wide confidence intervals indicate that results should be viewed with caution.

Estimations of One Repetition Maximum and Isometric Peak Torque in Knee Extension Based on the Relationship Between Force and Velocity

2016 ◽  
Vol 30 (4) ◽  
pp. 980-988 ◽  
Author(s):  
Yoshito Sugiura ◽  
Yasuhiko Hatanaka ◽  
Tomoaki Arai ◽  
Hiroaki Sakurai ◽  
Yoshikiyo Kanada
Keyword(s):  
Peak Torque ◽  
Knee Extension ◽  
Repetition Maximum ◽  
The Relationship

Skeletal muscle fatigue, strength, and quality in the elderly: the Health ABC Study

2005 ◽  
Vol 99 (1) ◽  
pp. 210-216 ◽  
Author(s):  
Andreas Katsiaras ◽  
Anne B. Newman ◽  
Andrea Kriska ◽  
Jennifer Brach ◽  
Shanthi Krishnaswami ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fatigue ◽  
Knee Flexion ◽  
Peak Torque ◽  
Older Men ◽  
Knee Extension ◽  
Muscle Quality ◽  
Knee Extensors ◽  
Men And Women ◽  
Skeletal Muscle Fatigue

We examined the muscle fatigue characteristics in older men and women and determined whether these were related to the size, strength, or quality of muscle. A total of 1,512 men and women aged 70–79 yr from the Health, Aging, and Body Composition Study participated in this study. Muscle cross-sectional area and attenuation were determined with computed tomography. Skeletal muscle fatigue and strength (peak torque) of the knee extensors and flexors were measured using isokinetic dynamometry. Men were more fatigue resistant than women for both knee extension (fatigue index: 70.4 ± 15.3 vs. 66.9 ± 14.3%; P < 0.05) and knee flexion (67.9 ± 16.4 vs. 64.9 ± 17.6%; P < 0.05). Peak torque and muscle quality (specific torque) were higher in men than women for knee extension (99.6 ± 28.2 vs. 63.0 ± 16.8 N·m and 1.62 ± 0.43 vs. 1.51 ± 0.39 N·m/cm2; both P < 0.05) and for knee flexion (74.0 ± 26.4 vs. 49.6 ± 15.9 N·m and 2.47 ± 1.29 vs. 2.22 ± 0.78 N·m/cm2; both P < 0.05). Total work and power output was greater in men compared with women for both the quadriceps (1,353 ± 451 vs. 832 ± 264 J and 87.7 ± 33.5 vs. 53.3 ± 19.2 W; both P < 0.05) and the hamstrings (741 ± 244 vs. 510 ± 141 J and 35.4 ± 16.0 vs. 23.7 ± 10.2 W; both P < 0.05). In both genders, the quadriceps was able to perform more work with greater power compared with the hamstrings. Those who were stronger actually had greater fatigue after adjusting for age, race, physical activity, and total body fat. In conclusion, older men were more fatigue resistant than women, although in both men and women greater fatigue was not related to muscle weakness.

Unique Characteristics of Quadriceps Muscle Morphology and Function in Older Tennis Players

2021 ◽  
pp. 1-8
Author(s):  
Akito Yoshiko ◽  
Moroe Beppu ◽  
Naoki Chosa ◽  
Kohei Watanabe
Keyword(s):  
Vastus Lateralis ◽  
Muscle Thickness ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Muscle Quality ◽  
Muscle Size ◽  
Echo Intensity ◽  
Tennis Players ◽  
Vastus Intermedius

We investigated the quadriceps muscle size and quantitative characteristics in older tennis players. Thirty-eight senior tennis players (70.8 ± 5.3 years) and 38 controls (71.6 ± 5.1 years) were included. To measure the muscle size and quality, we measured muscle thickness in the rectus femoris (RF), vastus lateralis, and vastus intermedius, and muscle echo intensity in the RF and vastus lateralis using B-mode transverse ultrasound, respectively. We measured knee extension peak torque for muscle function. Muscle thickness in the RF, vastus lateralis, and vastus intermedius were significantly larger in tennis players than in controls. Tennis players had a lower echo intensity in RF and a higher knee extension peak torque compared to controls. Stepwise multiple linear regression analysis implied that echo intensity and muscle thickness were predictors of knee extension peak torque. Higher muscle quality contributes to a higher knee extension peak torque in tennis players. Playing tennis may prevent age-related muscle atrophy and maintain muscle quality in older individuals.

Relationships among Muscle Endurance, Explosiveness, and Strength in Circum-Pubertal Boys

1998 ◽  
Vol 10 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Kensaku Suei ◽  
Leslie McGillis ◽  
Randy Calvert ◽  
Oded Bar-Or
Keyword(s):  
Body Mass ◽  
Vertical Jump ◽  
Peak Torque ◽  
Knee Extension ◽  
Muscle Performance ◽  
Muscle Endurance ◽  
Total Work ◽  
Endurance Strength ◽  
Isometric Knee Extension ◽  
Pubertal Boys

We assess relationships among muscle endurance, strength, and explosiveness in forty-eight 9.6- to 17.0-year-old males divided into 3 maturational groups (Tanner Stages I, II-IV, and V). Peak torque during isometric knee extension and flexion was averaged to reflect strength. Mechanical power in the Sargent vertical jump was taken as explosiveness, and total work in the Wingate test reflected muscle endurance. Correlations (3 groups combined) among the variables, expressed in absolute terms, were r = .82 to .92, but only -.11 to .70 when expressed per body mass or lean thigh size. These correlations were distinctly lower in the Tanner V boys than in the 2 less-mature groups, which may suggest that specialization into discrete muscle performance characteristics does not occur before late puberty.

scholarly journals Impaired muscle capacity of the hip and knee in individuals with isolated patellofemoral osteoarthritis: a cross-sectional study

2021 ◽  
Vol 12 ◽  
pp. 204062232110287
Author(s):  
Cristiano Carvalho ◽  
Fábio Viadanna Serrão ◽  
Letícia Mancini ◽  
Paula Regina Mendes da Silva Serrão
Keyword(s):  
Physical Functioning ◽  
Average Power ◽  
Peak Torque ◽  
Knee Extension ◽  
Cross Sectional Study ◽  
Healthy Controls ◽  
Patellofemoral Osteoarthritis ◽  
Total Work ◽  
Sectional Study ◽  
Cross Sectional

Aims: The aims of this study were to compare the capacity of the knee and hip muscles between individuals with and without isolated patellofemoral osteoarthritis (PFOA) and to evaluate the impact of PFOA on pain, stiffness, and physical function. Methods: This cross-sectional study evaluated muscle capacity of the hip and knee using an isokinetic dynamometer. The isokinetic variables used in the statistical analysis were peak torque, total work, and average power. Pain, stiffness, and physical function were assessed using questionnaires. Results: A total of 26 individuals participated in the study (13 with PFOA and 13 controls). The PFOA group exhibited lower peak torque, total work, and average power for knee extension and flexion in the concentric mode ( p ⩽ 0.01) as well as lower peak torque and total work for knee extension ( p ⩽ 0.005) and lower total work for knee flexion ( p = 0.05) in the eccentric mode. The PFOA group exhibited lower peak torque of the extensor, abductor, adductor, and internal rotator muscles of the hip ( p ⩽ 0.05), less total work of the abductor and adductor muscles ( p ⩽ 0.04), and lower average power of eccentric adduction of the hip ( p = 0.01) compared with the healthy controls. Compared with the control group, the PFOA group had a higher level of pain, stiffness, and compromised physical functioning self-reported ( p ⩽ 0.005). Conclusion: Participants with PFOA exhibited impairments regarding muscle capacity of the hip and knee, higher level of pain and stiffness as well as compromised physical functioning in comparison with healthy controls.

The Relationship between Lower Extremity Isokinetic Work and Single-Leg Functional Hop-Work Test

2006 ◽  
Vol 15 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Robert English ◽  
Mary Brannock ◽  
Wan Ting Chik ◽  
Laura S. Eastwood ◽  
Tim Uhl
Keyword(s):  
Body Weight ◽  
Lower Extremity ◽  
Outcome Measures ◽  
Study Design ◽  
Peak Torque ◽  
Knee Extension ◽  
Isokinetic Strength ◽  
Total Work ◽  
Lower Extremity Strength ◽  
The Relationship

Context:Lower extremity functional testing assesses strength, power, and neuro-muscular control. There are only moderate correlations between distance hopped and isokinetic strength measures.Objective:Determine if incorporating body weight in the single-leg hop for distance increases the correlation to isokinetic measures.Study Design:Correlational study.Setting:Musculoskeletal laboratory.Participants:30 healthy college students; 15 men and 15 women; ages 18 to 30 years.Main Outcome Measures:Isokinetic average peak torque and total work of quadriceps and hamstrings and single-leg hop work and distance.Results:Significant correlations include hop work to total-work knee extension (r= .89), average peak-torque knee extension (r= .88), distance hopped to total-work knee extension (r= .56) and average peak-torque knee extension (r= .63). Correlations involving hop work were greater than distance hopped (P< .05).Conclusions:Use of body weight in the assessment of distance hopped provides better information about the patient’s lower extremity strength and ability than the distance hopped alone.

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