Isokinetics and Exercise Science - Volume 18, issue 3

Authors: Zanca, Gisele G. | Camargo, Paula R. | Oliveira, Ana B. | Serrão, Paula R.M.S. | Mattiello-Rosa, Stela M.

Article Type: Research Article

Abstract: This study compared peak torque and torque steadiness during isometric lateral and medial rotations in workers with shoulder impingement syndrome (SIS) and those with no upper limb disorders. Twenty-nine female workers were evaluated. The SIS group consisted of 14 workers (36.57 ± 5.23 years) with unilateral SIS. The control group consisted of 15 healthy workers (35.53 ± 5.46 years). Three maximal voluntary isometric contractions (MVIC) of 5-s duration were performed to determine the peak …torque, which was used to calculate the target torque (50% MVIC). For assessment of the torque steadiness 3 trials were performed at the target torque for 5 s each, with visual feedback. Standard deviation (SD) and coefficient of variation (CV) were measured from the steadiness trials. Peak torque, SD and CV were not different (P> 0.05) between groups neither between affected and unaffected sides of the SIS group for both rotations. It was possible to suggest that torque steadiness, during isometric medial and lateral rotations of the shoulder, is not altered in workers with SIS when compared to healthy workers, and that maintenance of regular work activities may play an important role in preservation of the steadiness in this population. Show more

Keywords: Impingement, isometric force, MVIC, steadiness

DOI: 10.3233/IES-2010-0368

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 115-118, 2010

Authors: Radaelli, Régis | Bottaro, Martim | Weber, Fernanda | Brown, Lee E. | Pinto, Ronei S.

Article Type: Research Article

Abstract: The purpose of this study was to compare the effect of two different positions of shoulder internal rotation (IR) and external rotation (ER) on isokinetic concentric and eccentric peak torque as well as conventional and dynamic ratios. Nineteen athletes (Eigth judo and eleven tennis players), (20.3 ± 5.2 yrs) performed 5 maximal unilateral isokinetic concentric shoulder IR and ER repetitions at 60°/s and 120°/s. The subjects also performed 3 and 5 maximal …eccentric shoulder ER repetitions at 60°/s and 120°/s respectively. The tests were performed in two seated positions: 1) with the shoulder abducted in the scapular plane, and 2) with the shoulder flexed in the saggital plane. Shoulder dynamic control ratio (DCR) and conventional ratio were also assessed. The scapular plane position showed significantly (p < 0.05) greater peak torque (PT) values than the saggital plane position during concentric IR at both speeds. However, the saggital plane position PT values were significantly greater during concentric and eccentric ER in both speeds. Additionally, the DCR and the conventional ratio values were significantly greater for the saggital plane shoulder position. These results suggest that test position is an important control variable in isokinetic shoulder IR and ER testing. Show more

Keywords: Isokinetic, shoulder, muscle balance, external rotation, internal rotation

DOI: 10.3233/IES-2010-0369

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 119-124, 2010

Authors: Ambegaonkar, Jatin P. | Shultz, Sandra J.

Article Type: Research Article

Abstract: Surface electromyography(sEMG) is extensively used to examine muscle activation. Although raw sEMG signals are often filtered using Root-Mean-Square(RMS) algorithms, little agreement exists as to the time window over which signals should be processed. We examined the effects of differing RMS filtering windows on muscle onset times. Fifty-five participants performed 5 drop jumps from a 45 cm box and lateral gastrocnemius(LG), medial and lateral hamstring(MH, LH) and lateral quadriceps(LQ) muscle activity were acquired. …Signals were collected at 1000 Hz and RMS filtered using 3 ms, 10 ms, 20 ms and 25 ms windows. Muscle onset times differed by RMS windows for the LG(p= 0.01), MH(p= 0.002), and LH(p= 0.000), but not for the LQ(p=0.14). Pairwise comparisons indicated that LG onsets were earlier with the 3 ms vs. 20 ms window, MH onsets were earlier with the 3 ms vs. 20 ms and 25 ms windows, and LH onsets were earlier with the 3 ms, 10 ms, and 20 ms windows than the 25 ms window. Gastrocnemius and hamstring muscle onset times were substantially earlier when filtering raw sEMG data with 3 ms versus wider RMS windows(> 20 ms) during landing. Changing filtering parameters affects data interpretation when analyzing sEMG data using differing window widths. Additional research should determine optimal RMS window widths that maximize signal fidelity but still retain meaningful time differences. Show more

Keywords: Surface electromyography, root mean square, signal processing, drop jumps

DOI: 10.3233/IES-2010-0370

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 125-132, 2010

Authors: Bohannon, Richard W.

Article Type: Research Article

Abstract: This review used published data to describe the minimal detectable change for make test measurements of knee extension force obtained by hand-held dynamometry. Five studies involving patients contributed data. Depending on the study and side, the minimal detectable change ranged from 7.6 to 92.1 Newtons. These values provide an indication of how much a patient's knee extension force would need to change to conclude that a real alteration in status had occurred.

Keywords: Muscle strength, measurement, dynamometry

DOI: 10.3233/IES-2010-0371

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 133-135, 2010

Authors: Zatoń, M.W. | Hebisz, R.G. | Hebisz, P.

Article Type: Research Article

Abstract: The present experiment, which lasted for five weeks, was performed to investigate the effects of additional respiratory dead space on morphotic elements of blood. Twelve amateur mountain bikers were divided into two groups: experimental (E) and control (C). Apart from performing their daily training, the participants had three endurance training sessions per week: the experimental group with additional respiratory dead space (mask and tube – 1000 ml), the control group without any difficulty in respiration. The …haematocrit (HCT), hemoglobin (HGB), red blood cell (RBC), mean cell haemoglobin mass (MCH), mean cell volume (MCV), mean cell haemoglobin concentration (MCHC) and total work in progressive test for each subject were lab-measured before and after the experiment. Following the experiment HGB, HCT and RBC were significantly decreased only in E. Despite the above-mentioned changes, the amount of work performed by participants during the progressive test was significantly higher in the experimental group. Show more

Keywords: Haemoconcentration, additional respiratory dead space, cycling training

DOI: 10.3233/IES-2010-0372

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 137-143, 2010

Authors: Patlar, Suleyman

Article Type: Research Article

Abstract: The aim of this study is to investigate how does an acute 4-week submaximal exercise affect both leukocyte and leukocyte subgroups. The study registered 8 healthy male subjects. The subjects were exercised on Monark 814-E and 818 model ergometric bicycles 3 times a week for 4 weeks at above threshold heart rate and 75% of Max VO_{2} . Blood samples were collected three times from the subjects, before starting the exercise, immediately after finishing the last exercise …and 2 hours after the last exercise. The samples were analyzed in HemaCell Counter (Skits) apparatus to quantify leukocyte, neutrophil, monocyte, eosinophil and basophil levels. Leukocyte counts obtained in both post-exercise measurements were significantly higher than those before the exercise (p< 0.05). Neutrophil percentages two hours after exercise were higher than those before and immediately after exercise (p< 0.05). Lymphocyte percentages obtained just after exercise were elevated in comparison to those both before and two hours after exercise (p< 0.05). However, lymphocyte percentages two hours after exercise were significantly lower than the pre- and post-exercise percentages (p< 0.05). Percentages of monocytes, eosinophils and basophils in both post-exercise measurements were lower relative to pre-exercise values (p<0.05). In conclusion both acute and 4-week submaximal exercise have significant effects on leukocyte and leukocyte subgroups. Show more

Keywords: Submaximal exercise, leukocyte, leukocyte subgroups

DOI: 10.3233/IES-2010-0373

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 145-148, 2010

Authors: Adedoyin, Rufus A. | Mbada, Chidozie E. | Odiachi, Adaobi M. | Adegoke, Babatunde O.A. | Awotidebe, Taofeek O.

Article Type: Research Article

Abstract: Background and objective: Empirical research on the influence of smoking on musculoskeletal health in athletes is sparse. The objective of this study was to compare back extensor muscles' strength (BEMS) before and after a fatigue induction protocol among smoking and non smoking male athletes. A pretest-posttest design was used to determine the difference in BEMS between smoking (N=52) and non smoking (N=52) athletes aged 18 and 30. A back and leg dynamometer was used to quantify …BEMS while repetitive prone chest raise test was used to induce fatigue of the back extensor muscles. The smoking (23.1 ± 2.9 years) and non-smoking athletes (23.2 ± 2.37 years) were comparable in age (p= 0.855). Smoking athletes exhibited a significantly higher rating of perceived exertion (p=0.007) and fatigue index (10.76% vs. 5.07%); and significant reduction in BEMS following fatigue induction (p < 0.05) compared with their non smoking counterparts. Smoking athletes have higher rates of muscular fatiguability and decreased back strength following back extensors tasks. Smoking is associated with increased muscle fatiguability and impairment of back strength in athletes. Show more

Keywords: Back extensors, dynamometer, muscle strength, smoking, athletes

DOI: 10.3233/IES-2010-0377

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 149-155, 2010

Authors: Akkurt, Ekrem | Salli, Ali | Ozerbil, Onder Murat | Ugurlu, Hatice

Article Type: Research Article

Abstract: The aim of this study was to evaluate VMO and VL EMG activation onset times (AOT) during isometric contractions at various degrees of knee flexion and to explore the effects of a 6-w isokinetic exercises program on pain, quality of life, muscle strength and, if observed, on the difference in AOT, in patients with patellofemoral pain syndrome (PFPS). Twenty two female patients suffering from anterior knee pain and diagnosed with PFPS were recruited. The main outcome …measures consisted of AOT and maximal isometric contraction of VMO and VL muscle and Medical Outcomes Study (SF36) and VAS scores. Compared to control knees, pre-exercise measurements revealed significant delay only in VMO at knee flexion angles of 15°, 30°, 45°. Post-exercise measurements showed improvement in the delay at 15°, 30°, 45° and also in the other pain, health quality and muscle strength measurements. In conclusion; VMO is activated later than VL in PFPS patients while exercise results in improvements in both symptoms and delay in VMO. Show more

Keywords: Patellofemoral pain syndrome, isokinetic exercise, EMG, knee

DOI: 10.3233/IES-2010-0378

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 157-161, 2010

Authors: Cai, Zong-Yan | Hsu, Cheng-Chen | Su, Chin-Peng | Lin, Chin-Fan | Lin, Yi-An | Lin, Chin-Li | Hsu, Mei-Chich

Article Type: Research Article

Abstract: We compared the lower limb muscle activation during uphill running (UR), level running (LR), and downhill running (DR). Eight male physically active subjects ran three slopes for 30 min at the given speed (55% vVO_{2} peak at LR), including DR (−6°), LR (0°), and UR (6°) in a random crossover, repeated measures design. Electromyographic (EMG) signals were collected from the dominated lower limb muscles: rectus femoris (RF), biceps femoris (BF), gastrocnemius (GAS), soleus, …and tibialis anterior. Our results showed that greater EMG of RF was found with inclining slope (UR>LR>DR, p< 0.05); EMG of BF was greater during UR than during DR (p< 0.05); EMG of GAS differed significantly in the order: UR>DR>LR (p< 0.05). We concluded that significant differences regarding muscle activations among DR, LR, and UR were observed for the RF, BF, and GAS, especially when running opposing slopes (DR vs. UR). Additionally, when running toward uphill, the propulsive muscles, such as the RF and GAS seemed to exert more effort. In contrast, while running toward downhill, RF might work as an extensor muscle that was activated to a lesser extent, possibly due to its undergoing eccentric movement. Show more

Keywords: Slope, electromyography, incline, eccentric exercise

DOI: 10.3233/IES-2010-0379

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 163-168, 2010

Authors: Olivier, Pierre | du Toit, Ettienne | du Randt, Rosa | Venter, Danie

Article Type: Research Article

Abstract: The variety of measurement devices and protocols being used to assess neck muscle strength hampers the comparison of data and the generation of reference data. Little is known about dynamic neck muscle strength because a limited amount of research using isokinetic dynamometry as assessment method has been published. The purpose of the research on which this article is based was therefore to delineate and generate reference data for the dynamic isokinetic neck muscle strength of adults …aged 19 to 69 years old, based on a purpose-built isokinetic measurement device. Measurements were made through the frontal and sagittal planes of movement. Furthermore, the data, categorised into ten gender discriminate age categories of ten years each, were statistically analysed to detect significant differences between the categories. Four hundred and fifty-two volunteers, consisting of 221 males and 231 females, were assessed. Reference data stratified according to the gender discriminate age categories and based on 95% confidence intervals were generated. Statistical analyses however indicated that significant differences were predominantly between males and females, irrespective of age. This justifies the use of reference data grouped according to gender and questions whether age should be considered as a stratification factor when generating neck muscle strength reference data. Show more

Keywords: Isokinetics, neck muscle strength, reference data

DOI: 10.3233/IES-2010-0380

Citation: Isokinetics and Exercise Science, vol. 18, no. 3, pp. 169-177, 2010