Isokinetics and Exercise Science - Volume 16, issue 1

Authors: Finlayson, Michele H.M. | Majerus, Amber L. | Temes, Amy L. | Wright, Allison M. | Gajdosik, Richard L.

Article Type: Research Article

Abstract: This study examined the effects of an isometric fatiguing exercise on selected length and passive-elastic properties of the calf muscle-tendon unit (MTU). The right calf MTU of 8 minimally active women 22–34 years of age were stretched by a Kin-Com® dynamometer motor from plantarflexion to a constant maximal dorsiflexion (DF) angle at 5°ċ s^{-1} to measure angular and resistive torque differences before and immediately after an isometric fatiguing exercise. Minimal …surface electromyogram (EMG) activity from the soleus, gastrocnemius and tibialis anterior muscles ensured the stretches were passive. The muscles were fatigued by 60 s isometric plantarflexion trials at 80% of the maximal voluntary contraction (MVC) force with 15 s rests between trials until the force fell below 50% MVC, which was associated with increased EMG activity of the plantarflexors. One-way ANOVAs showed that the initial passive DF angle and therefore the length extensibility did not change. The maximal and mean passive DF torque and the area under the curve also did not change, but the full stretch average passive-elastic stiffness increased (P=0.005). The results suggested that the length and passive resistive properties of the calf MTU are maintained and the average passive-elastic stiffness is increased after an active isometric fatiguing exercise. Show more

Keywords: Calf muscle-tendon unit, length extensibility, passive resistance, passive-elastic stiffness, isometric fatigue

DOI: 10.3233/IES-2008-0289

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 1-9, 2008

Authors: Horvais, Nicolas | Samozino, Pierre | Textoris, Vincent | Hautier, Christophe | Hintzy, Frederique

Article Type: Research Article

Abstract: The aim of this study was to describe elliptical cycle locomotion by muscular, kinematics, physiological and perceptual parameters during submaximal and maximal exercises. Seven men performed an incremental test until exhaustion. Pulse rate, ratings of perceived exertion (6–20 Borg's scale), muscular activity of 8 muscles (higher and lower limbs muscles) and elbow, shoulder, hip and knee joint amplitudes were continuously recorded. Pulse rate reached about 70% of the theoretical maximal pulse rate after 3 minutes of …submaximal exercise and about 95% at the end of the maximal exercise; the sensation of this effort being respectively described as "weak" and "very hard". EMG analysis indicated that all investigated muscles were activated, especially knee and hip extensor muscles. Kinematic analysis showed that all joints were activated especially the elbow, shoulder and knee. The elliptical cycle locomotion led to global body activation (both higher and lower limbs activity) and therefore induced a relatively significant cardiac activation even at low intensity. We therefore suggest that elliptical cycle locomotion is a unique pattern. Show more

Keywords: Fitness, ergometer, electromyography, kinematics, perception, innovation

DOI: 10.3233/IES-2008-0290

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 11-17, 2008

Authors: Muraki, Satoshi | Tsunawake, Noriaki

Article Type: Research Article

Abstract: The purpose of this study was to investigate the influences of pedaling rate during passive leg cycling (PLC) on respiratory and cardiac responses in able-bodied subjects. Ten male and ten female subjects performed PLC on an electric motor-controlled ergometer that provides constant-rate pedaling. After PLC at 20 rpm for 5 min, the pedaling rate was gradually increased by 5 rpm every 1 min until 70 rpm was attained. Gas exchange responses, heart rate, and muscle oxygenation …were measured during rest and PLC. The increases in ventilation, oxygen uptake, and heart rate in both sexes accelerated when the pedaling rate exceeded a threshold of between 20–45 rpm. Over this threshold, they increased linearly, not exponentially. These results suggest that respiratory and cardiac responses were influenced by the pedaling rate during PLC and were promoted at a low pedaling rate. Show more

Keywords: Passive leg cycling, pedaling rate, respiratory response, heart rate, venous return

DOI: 10.3233/IES-2008-0291

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 19-24, 2008

Authors: Eyigor, Sibel | Kirazli, Yesim | Capaci, Kazım | Oder, Gonca | Tarhan, Figen | Inal, Vedat

Article Type: Research Article

Abstract: Backgroud and objectives: In patients with rheumatoid arthritis (RA), some muscle groups are affected in different stages of disease, especially those related to the affected joint. However, data on associations between functional performance and muscle strength in RA are few. Therefore we sought to determine whether isokinetic ankle plantarflexion (PF) and dorsiflexion (DF) strength was affected in RA patients and to study the association between isokinetic strength and other clinical indicators of …disability such as walking and stair-climbing time and disease activity in patients with RA. Methods: Thirty three patients diagnosed with RA in the chronic phase were selected from a rheumatology outpatient clinic and matched for age and gender with 33 healthy subjects. Isometric and isokinetic muscle strength was measured in DF and PF. The subjects were also evaluated through the Stanford Health Assessment Questionaire (HAQ), walking and stair-climbing time. Cumulative and current steroid doses (CSD) were calculated. Results: No significant correlations were found between muscle strength and visual analogue scale (VAS) scores, HAQ, ankle involvement, CSD (p>0.05). With respect to the isokinetic parameters, no differences have been been observed between RA and control groups (p>0.05). Walking and stair-climbing time increased significantly (p<0.05) in patients with RA. Conclusions: Ankle isokinetic muscle strength is not affected in inactive RA patients while negative effects of steroids on muscle strength were not demonstrated. Important determinators of walking ability in RA patients should be defined in future studies. Show more

Keywords: Rheumatoid arthritis, ankle, isokinetic muscle strength

DOI: 10.3233/IES-2008-0292

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 25-31, 2008

Authors: Nicolas, A. | Gauthier, A. | Bessot, N. | Moussay, S. | Thibault, G. | Sesboüé, B. | Davenne, D.

Article Type: Research Article

Abstract: We investigated the effect on neuromuscular properties of the knee extensors of an exhaustive cycling exercise performed at 6AM and 6PM. Eleven well trained cyclists performed a maximal aerobic exercise consisting in a sustained effort at 95% of their maximal power until exhaustion (T_{lim} ). Isometric maximal voluntary contraction (MVC) and electromyographic activities (root mean square: RMS) of the vastus lateralis were recorded before (pre-test) and immediately after (post-test) the cycling …exercise. The MVC/RMS ratio was calculated and used as an index of neuromuscular efficiency (NME). Rectal temperature was recorded continuously throughout the test session. Results show that T_{lim} cycling exercise was not time-of-day dependent (p=0.42). A significant interaction effect of time of day and the cycling exercise was demonstrated for MVC (p<0.02) and NME (p<0.05). In pre-test, MVC and NME were higher in the late afternoon than in the morning (+6.8%); however both parameters were more affected by the T_{lim} exercise at 6PM than at 6AM. These results suggest that following cycling T_{lim} exercise, neuromuscular properties of the knee extensors are more affected in the evening than in the morning. However, circadian rhythm of some biomechanical parameters implicated in the pedalling movement may modulate the effect of these diurnal variations. Show more

Keywords: Diurnal variation, muscle fatigue, electromyography, limited time, MVC

DOI: 10.3233/IES-2008-0293

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 33-40, 2008

Authors: Papadopoulos, Christos | Kalapotharakos, Vasilios I. | Chimonidis, Evripidis | Gantiraga, Evaggelia | Grezios, Apostolos | Gissis, Ioannis

Article Type: Research Article

Abstract: The aim of the present study was to examine the effect of knee joint angles on maximal voluntary contraction (MVC) of leg extensor and electromyographic (EMG) activities of rectus femoris (RF), vastus medialis (VM), and biceps femoris (BF) during a maximal isometric leg press task. Eighteen males, aged 18–23, performed maximum bilateral voluntary isometric contractions at five knee joint angles (90°, 80°, 70°, 60°, and 50°; 0°= full extension). The MVC of …leg extensors, the force exerted during the first 100~ms of the contraction (F100), the time achieved the MVC, and the average integrated EMG activities (AEMG) of RF, VM, and BF were measured at five knee joint angles. MVC was significantly higher (p<0.05) at 60° in comparison to the other knee joint angles, whereas AEMGs of RF and VM were significantly lower (p<0.05) at more extended position (50° than at more flexed positions (90°, 80°, and 70°). AEMG of BF did not present significant changes among the five different knee joint angles. These findings suggest that MVC of leg extensor are considerably influenced by the mechanical force-length properties of skeletal muscle. The reduced activation of RF at more extended knee positions indicates its multiple function along a closed chain multi-joint task. On contrary, the similar activation of biceps femoris muscle at all five knee joint angles indicates its importance for the knee joint stability. Show more

Keywords: Isometric force, muscle length, activation, quadriceps femoris muscle

DOI: 10.3233/IES-2008-0294

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 41-46, 2008

Authors: O'Sullivan, Anita | O'Sullivan, Kieran

Article Type: Research Article

Abstract: The purpose of this study was to compare isokinetic concentric quadriceps and hamstring performance in healthy females in the absence of feedback versus combined visual feedback and verbal encouragement at 60, 180 and 300°/s. A repeated-measures randomised cross-over design was used. Twenty two asymptomatic females were tested at the three test velocities under two randomly ordered conditions: (a) combined visual feedback and verbal encouragement; and (b) no feedback. The two sessions were separated …by seven days. Examination of results revealed that with feedback there was a statistically significant increase in peak torque at the three test velocities (p<0.05) for both muscles. This study demonstrated that combined feedback can result in increased concentric muscle performance in females at three test velocities. Show more

Keywords: Feedback, isokinetics, muscle, knee

DOI: 10.3233/IES-2008-0295

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 47-53, 2008

Authors: Ozcaldiran, Bahtiyar

Article Type: Research Article

Abstract: Our purpose was to compare muscle flexibility and strength for lower extremities in the different groups determined by sport and to investigate the relationship between these parameters. We evaluated a total 62 subjects consisting of 19 swimmers, 23 soccer players and 20 controls with four flexibility tests. Isokinetic muscle evaluation of knee flexors and extensors was carried out for all subjects. All the results were significantly different among the groups without a difference between the athletes. …The results showed that there was no significant relationship between the strength and flexibility in the athletes. A relationship between flexibility and strength at 60°/s was also indicated in swimmers and soccer players. Show more

Keywords: Flexibility, dynamometer, torque, knee

DOI: 10.3233/IES-2008-0296

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 55-59, 2008

Authors: Çetin, Nuri | Dilek, Ayse | Aytar, Aydan | Akman, Mahmut Nafiz

Article Type: Research Article

Abstract: We aimed to determine the test-retest reproducibility of isokinetic dynamometric measurement of the resistance to passive motion for quantitative evaluation of wrist flexor spasticity in stroke patients. In a repeated measures design, 2 raters tested each subject 3 times on 6 separate days. Twenty one sub-acute/chronic stroke patients 55 ± 14.1 years of age with an average disease duration of 7.04 ± 2.87 months volunteered to take part along with 20 age-matched healthy …controls. Clinical assessment of spasticity was performed using an Ashworth Scale. Resistance measurements of 5 consecutive flexion/extension movements of the wrists were performed at 3 reselected angular velocities (10°/s, 30°/s, 45°/s), using a computerized dynamometer, set in the continuous passive joint motion mode. The maximum peak torque values in for each subject were calculated for each set of repetitions. The reproducibility of strength measurements were evaluated using single-measure and average-measure intra class correlation coefficients (ICCs). There was a significant positive correlation between Ashworth Scale and torque values. Torque values were significantly higher in groups with patients who had strokes than in the control group. The dynamometric scores were positively correlated with Ashworth Scale grades. The ICCs for intra-tester measurements were high and ranged 0.82–0.87. The Bland-Altman plots indicated no systematic bias. The standard error of measurement (SEM) ranged 0.27–0.38 Nm while the smallest real difference (SRD) ranged −1.0 Nm to 1.1 Nm). These values correspond to a mean SEM% of 31% and SRD% of 85%. These values indicate relatively large measurement error and thus does not support the use of isokinetic dynamometry, using this protocol and measurement system, in assessing wrist muscles spasticity in stroke patients. Show more

Keywords: Spasticity, isokinetic dynamometry, reproducibility, stroke

DOI: 10.3233/IES-2008-0297

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 61-67, 2008

Authors: Surenkok, Ozgur | Aytar, Aydan | Tüzün, Emine Handan | Akman, Mahmut N.

Article Type: Research Article

Abstract: This study sought to assess knee joint position sense(JPS) and static balance after application of cold-packs and spray. Fifteen healthy basketball players volunteered to participate. Each subject underwent testing first after cold pack application and then 1-week later cold spray application. JPS, around-the-knee pain threshold, and 1-leg static balance were assessed in all patients before and after cryotherapy. JPS was measured with an isokinetic dynamometer. Static balance was assessed using a kinesthetic ability trainer. A …pressure algometer was used to measure pressure pain thresholds. Knees were tested using continuous passive motion (CPM). Flexion and extension ranged from 0 to 90 degrees; passive movement was maintained at a velocity of 5 degrees per second. Knee movement in both directions was stopped by pressing a button at the mid point (45°) as a reference point. Regarding 1-leg static balance scores, significant differences were found before and after cold pack application and between knee JPS and pain scores. Significant differences also were found for JPS before and after cold spray application and between JPS scores and pain; however, results on the 1-leg balance tests showed no significant differences. No significant differences were found for 1-leg static balance scores at 5 minutes after cryotherapy application. In this study, we showed that JPS deficits occurred, and postural control was adversely affected, with cryotherapy, and caution should be observed when athletes immediately return to their chosen sport after cryotherapy application. Show more

Keywords: Balance, fatigue, cryotherapy

DOI: 10.3233/IES-2008-0298

Citation: Isokinetics and Exercise Science, vol. 16, no. 1, pp. 69-73, 2008