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Cardiovascular Responses to Submaximal Concentric and Eccentric Isokinetic Exercise in Older Adults

Elizabeth Thompson, Theo H. Versteegh, Tom J. Overend, Trevor B. Birmingham, and Anthony A. Vandervoort

Our purpose was to describe heart rate (HR), mean arterial blood pressure (MAP), and perceived exertion (RPE) responses to submaximal isokinetic concentric (CON) and eccentric (ECC) exercise at the same absolute torque output in older adults. Peak torques for ECC and CON knee extension were determined in healthy older males (n = 13) and females (n = 7). Subjects then performed separate, randomly ordered, 2-min bouts of CON and ECC exercise. Heart rate and MAP increased (p < .001) from resting values throughout both exercise bouts. CON exercise elicited a significantly greater cardiovascular response than ECC exercise after 60 s. Peak HR, MAP, and RPE after CON exercise were greater than after ECC exercise (p < .01). At the same absolute torque output, isokinetic CON knee extension exercise resulted in a significantly greater level of cardiovascular stress than ECC exercise. These results are relevant to resistance testing and exercise in older people.

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Allithiamine Ingestion Does Not Enhance Isokinetic Parameters of Muscle Performance

Matthew R. Doyle, Michael J. Webster, and Loran D. Erdmann

The purpose of this study was to investigate the effect of oral allithiamine administration on isokinetic parameters of muscle performance and lactate accumulation prior to, during, and in recovery from isokinetic exercise. A double-blind, counterbalanced, crossover experimental design utilizing aBiodex System 2 Isokinetic Dynamometer was used to test 15 healthy college students. Subjects orally ingested either 1 g · day 1 of a thiamin derivative, allithiamine, or a placebo for 5 days and then performed six exercise sets of knee extension and flexion. ANOVA revealed no significant differences between treatment conditions in peak torque, mean peak torque, average power, or total work performed (p > .05). Likewise, lactate accumulation was not significantly different between treatment conditions at any measurement point (p > .05). The absence of significant differences suggests that oral allithiamine administration does not enhance isokinetic parameters of muscle performance or lactate accumulation prior to, during, and following isokinetic exercise.

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Role of Body and Joint Position on Isokinetic Exercise and Testing

Donna D. Smith

This paper reviews the role of body and joint position during isokinetic exercise and testing. Due to the frequent implementation of isokinetic devices, it is important to examine the methodology of their use. Positioning of the subject and the target joint is a critical component of the methodology. The literature reveals significant relationships between the position of the subject and outcome measures such as torque, agonist-antagonist ratios, peak torque to body weight ratios, and reliability. These relationships are evidenced at the larger joints of the lower extremity, such as the hip, knee, and ankle, in addition to the shoulder joint of the upper extremity. Therefore, it behooves clinicians to review research regarding the effect of varied body and joint positions on outcome measures and regarding the relevance of specific positions to the predetermined goals.

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Effects of Isokinetic Exercise on Adolescents with Cerebral Palsy

Jeffrey A. McCubbin and Gregory B. Shasby

The purpose of this study was to examine the effects of isokinetic resistance exercise on torque development and movement time of individuals with cerebral palsy. Subjects (N = 30) 10 to 20 years of age were matched and assigned to one of three treatment groups: IR, isokinetic resistance; NR, repetitive practice with no resistance; and C, control. The treatment protocol consisted of exercising the tricep extensor group with 3 sets of 10 maximal speed repetitions, 3 times per week for 6 weeks. Data were collected for movement time on the Dekan Performance Analyzer with adapted photoelectric switches. Torque data were collected on the Cybex II with dual channel recorder. Significant differences (p < .05) occurred on both movement time and torque development for the isokinetically trained group. It was concluded that isokinetic resistance exercise affected neuromuscular performance in these youths with cerebral palsy similar to the nonhandicapped population.

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Effects of Concentric and Eccentric Strength Training on Fatigue Induced by Concentric and Eccentric Exercises

Eduardo Lusa Cadore, Miriam González-Izal, Rafael Grazioli, Igor Setuain, Ronei Silveira Pinto, and Mikel Izquierdo

during isokinetic exercise (ie, ECC vs CON), and both training groups showed similar decreases in concentric and eccentric peak torques when comparing pretraining and posttraining. In addition, the MVC showed an important specificity effect because GCON presented lower decreases after the CON protocol

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Evaluation of Shoulder Instability Braces

Mark DeCarlo, Kathy Malone, Brad Gerig, and Mike Hunker

The comparative abilities of three types of shoulder orthoses to limit motion following isokinetic exercise were studied on 10 male subjects. Maximum active abduction, forward flexion, and external rotation were measured under a control and three braced conditions. Braced conditions included Sawa, Duke Wyre, and Shoulder Subluxation Inhibitor. Subjects performed 10 repetitions each of flexion/extension and abduction/adduction exercise at isokinetic speeds of 120 and 180°/s. Data were analyzed using a paired t-test and ANOVA. Significant differences were found for each of the devices in pre/post gonio-metric measurements of forward shoulder flexion. Only the Sawa brace demonstrated significant pre/post change for shoulder abduction. No significant differences were detected in any of the devices for external rotation. A trainer who is selecting a motion-limiting shoulder device for an athlete returning to competition following injury should consider the “loosening” effect that may occur during activity as well as the desire for overhead motion.

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Effects of Downhill Running on the Responses to an Oral Glucose Challenge

William M. Sherman, Julie M. Lash, John C. Simonsen, and Susan A. Bloomfield

Because muscle damage from eccentric exercise has been associated with alterations in muscle glycogen metabolism, this study determined the effects of exercise on the insulin and glucose responses to an oral glucose tolerance test (OGTT). In a repeated-measures design, 11 subjects undertook either no exercise, 2 min of isokinetic leg exercise, or 50 min of level or downhill running. No exercise was performed and diet was controlled during the 48 hrs after the treatments and before the OGTT. Ratings of muscle soreness and CK activity were significantly elevated 48 hrs after downhill running. Level running also increased CK activity but did not induce muscle soreness. Isokinetic exercise did not affect either one. Blood glucose responses to the OGTT were similar among the treatments. In contrast, the insulin responses to the OGTT following downhill running were significantly increased. These results suggest that eccentric exercise associated with downhill running that results in delayed muscle soreness is associated with the development of a mild insulin-resistant condition.

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Effect of Creatine Supplementation on Body Composition and Performance: A Meta-analysis

J. David Branch

Background: Creatine supplementation (CS) has been reported to increase body mass and improve performance in high-intensity, short-duration exercise tasks. Research on CS, most of which has come into existence since 1994, has been the focus of several qualitative reviews, but only one meta-analysis, which was conducted with a limited number of studies. Purpose: This study compared the effects of CS on effect size (ES) for body composition (BC) variables (mass and lean body mass), duration and intensity (≤30 s, [ATP-PCr = A]; 30–150 s [glycolysis = G]; >150 s, [oxidative phosphorylation = O]) of the exercise task, type of exercise task (single, repetitive, laboratory, field, upper-body, lower-body), CS duration (loading, maintenance), and subject characteristics (gender, training status). Methods: A search of MEDLINE and SPORTDiscus using the phrase “creatine supplementation” revealed 96 English-language, peer-reviewed papers (100 studies), which included randomized group formation, a placebo control, and human subjects who were blinded to treatments. ES was calculated for each body composition and performance variable. Results: Small, but significant (ES > 0, p ≤ .05) ES were reported for BC (n = 163, mean ± SE = 0.17 ± 0.03), ATP-PCr (n = 17, 0.24 ± 0.02), G (n = 135, 0.19 ± 0.05), and O (n = 69, 0.20 ± 0.07). ES was greater for change in BC following a loading-only CS regimen (0.26 ± 0.03, p = .0003) compared to a maintenance regimen (0.04 ± 0.05), for repetitive-bout (0.25 ± 0.03, p = .028) compared to single-bout (0.18 ± 0.02) exercise, and for upper-body exercise (0.42 ± 0.07, p < .0001) compared to lower (0.21 ± 0.02) and total body (0.13 ± 0.04) exercise. ES for laboratory-based tasks (e.g., isometric/isotonic/isokinetic exercise, 0.25 ± 0.02) were greater (p = .014) than those observed for field-based tasks (e.g., running, swimming, 0.14 ± 0.04). There were no differences in BC or performance ES between males and females or between trained and untrained subjects. Conclusion: ES was greater for changes in lean body mass following short-term CS, repetitive-bout laboratory-based exercise tasks ≤ 30 s (e.g., isometric, isokinetic, and isotonic resistance exercise), and upper-body exercise. CS does not appear to be effective in improving running and swimming performance. There is no evidence in the literature of an effect of gender or training status on ES following CS.

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The Importance of Functional Hamstring/Quadriceps Ratios in Knee Osteoarthritis

Özlem Aslan, Elif Balevi Batur, and Jale Meray

contraction occurs during leg flexion. 12 , 13 Thus, it is crucial to determine the affected muscle groups’ contraction mode before planning the isokinetic exercise program in rehabilitation. The use of functional hamstring/quadriceps (H/Q) ratio (Heccentric/Qconcentric [Hecc/Qcon], Hcon/Qecc) is mostly

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Effectiveness of Unilateral Training of the Uninjured Limb on Muscle Strength and Knee Function of Patients With Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis of Cross-Education

Iván Cuyul-Vásquez, Eliana Álvarez, Ariel Riquelme, Rocio Zimmermann, and Felipe Araya-Quintanilla

EG2 = 4.42 [1.75] mo GC = 3.67 [1.78] mo EG1 = standard rehabilitation + CE CEE EG2 = standard rehabilitation + CE CEE CG = standard rehabilitation Standard rehabilitation: Endurance training (biking), progressive resistance training, balance, and plyometric exercise. Isokinetic exercise with