Isokinetics and Exercise Science - Volume 21, issue 3

Authors: Wilhelm, Eurico N. | Radaelli, Regis | da Silva, Bruna G.C. | Botton, Cíntia E. | Barbosa, Rafael | Bottaro, Martim | Brown, Lee E. | Pinto, Ronei S.

Article Type: Research Article

Abstract: BACKGROUND AND OBJECTIVE: The quadriceps rate of torque development (RTD) is frequently used to evaluate explosive performance, but its functional meaning has been questioned. Thus, the aim of this study was to investigate if isometric quadriceps RTD correlates with multi-joint dynamic performance and if it has greater correlation with dynamic performance than with a single-joint isokinetic test in soccer players. METHODS: Thirty-nine male soccer players (age 21 ± 5 years, body mass 75 ± …7.5 kg, height 179 ± 5 cm) performed five maximal concentric knee extension isokinetic contractions at a velocity of 180°/s, followed by three maximal voluntary isometric contractions (MVIC) with knee angle of 60°, and five countermovement jumps (CMJ). The RTD was derived from MIVC over various time intervals (of 0.05, 0.1, 0.2, 0.3 seconds, and peak RTD) and CMJ height was calculated by flight time method. Pearson Product Moment Correlations were used to determine the relationships between variables. RESULTS: Absolute and relative isokinetic PT correlated positively with CMJ height (p< 0.001, r=0.513 and p=0.0007, r=0.521, respectively). However, none of the isometric RTD measures showed significant relationship with CMJ height (p> 0.05, r from −0.272 to 0.296). CONCLUSION: These results indicate that single-joint isometric RTD does not correlate with dynamic multi-joint performance. Thus, more specific tests in relation to contraction type, velocity and/or movement pattern should be used. Show more

Keywords: Peak torque, muscle strength, muscle power, knee extension

DOI: 10.3233/IES-130513

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 181-186, 2013

Authors: Watanabe, Hiroyuki | Abe, Hiroshi | Tojima, Michio | Yoshimoto, Masumi | Takahira, Naonobu | Torii, Suguru

Article Type: Research Article

Abstract: OBJECTIVE: The purpose of this study was to clarify the characteristics of abdominal deep muscles in adolescent soccer players. METHODS: Participants were 53 soccer players from junior high school and 14 adult soccer players. The deep abdominal muscles of both sides were imaged by ultrasonography. Abdominal muscles on the dominant leg side were selected as the targets of measurements, and measurements of the transversus abdominis (TrA) and internal oblique (IO) muscle were conducted. The muscle …thickness of these muscles was measured at rest and during contraction (while drawing-in of the abdominal wall) and served as the basis for comparing the adolescent and adult players. RESULTS: While no significant inter-group differences were noted in the thickness of the TrA or IO muscle at rest, a significant difference was observed during the drawing-in maneuver. CONCLUSION: The deep abdominal muscles of adolescent soccer players have not likely reached full maturity. Show more

Keywords: Ultrasound image, transverses abdominis muscle, internal oblique muscle, adolescent soccer player

DOI: 10.3233/IES-130512

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 187-193, 2013

Authors: Dirnberger, Johannes | Huber, Christoph | Hoop, Dennis | Kösters, Alexander | Müller, Erich

Article Type: Research Article

Abstract: BACKGROUND: Several investigations have reported reproducibility for isokinetic single-joint (SJ) knee strength measurements. However, to date, only a few studies have concentrated on multi-joint (MJ) leg strength measurements. OBJECTIVE: This study is the first to investigate reproducibility for MJ leg strength measurements using the IsoMed 2000-system, which recently was introduced into the market. METHODS: Peak Force (PF) of forty-one healthy male subjects (mean age: 24.4 years) performing concentric and eccentric MJ leg …extension at standardized mean knee-joint angular velocities 40 and 80°/s (i.e. individual linear foot velocities of 0.12–0.19 and 0.24–0.38 m/s, respectively) was measured in three identical sessions (T1–T3), separated by 10–14 days. Repeated measures analysis of variance (ANOVA) was applied for detection of systematic errors over sessions. Reproducibility was calculated between consecutive pairs of sessions (T1–T2; T2–T3) using intra-class correlation coefficients (ICC 2,1) and standard error of measurement (SEM). RESULTS: Significant increases in mean measurement values of ≈ 2–4% from T1 to T2/T3 could be seen for concentric measurements at 40°/s and overall eccentric measurements. Reproducibility calculations revealed ICC-values of 0.823–0.956 and 0.911–0.978 with corresponding measures of SEM of 72.1–175.3 and 49.3–125.3 N for T1–T2 and T2–T3, respectively. CONCLUSIONS: Moderate to high reproducibility was shown for the IsoMed 2000-system in measuring PF during concentric and eccentric isokinetic leg extension. However, as data indicate the presence of an initial practice-based improvement, we recommend the consideration of a familiarisation session in practice. Show more

Keywords: Reproducibility, practice-based improvement, maximum strength testing, leg press, IsoMed 2000

DOI: 10.3233/IES-130511

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 195-202, 2013

Authors: Bini, Rodrigo R. | Hume, Patria A.

Article Type: Research Article

Abstract: BACKGROUND: Reliability of pedal forces during cycling specific tests needs to be established if pedal forces are to be used in longitudinal studies evaluating performance improvements. METHOD: We assessed the reliability of pedal force measures during two incremental cycling tests to exhaustion separated by two to seven days. The number of competitive cyclists completing each workload increment varied (n=10 for 100 W to 250 W; n=8 for 300 W; n=6 for 350 W). Pedal forces were measured …via strain gauge instrumented pedals and pedal-to-crank angles via angular potentiometers attached to the pedal spindles. Mean and standard deviations, typical error of measurement percentage (TE%) and effect sizes (ES) between days across workloads for oxygen uptake (VO_{2} ), peak normal force (PNF), peak anterior-posterior force (PAPF), average total force on the pedal (ATF) and index of effectiveness percentage (IE) for right and left pedals were calculated. RESULTS: Averages across all workloads showed high reliability and trivial differences between two to seven days of testing for all variables (TE%, ICC, ES; VO_{2} =4%, 0.94, 0.1; PNFright=6%, 0.98, 0.1; PNFleft=12%, 0.98, 0.1; PAPFright=13%, 0.95, 0.2; PAPFleft=14%, 0.96, 0.1; ATFright=5%, 0.98, 0.1; ATFleft=11%, 0.97, 0.1; IEright=10%, 0.94, 0.2; IEleft=14%, 0.91, 0.1). CONCLUSION: Pedal force measures during incremental cycling tests to exhaustion can be used to assess changes in performance given the high reliability reported in our study. Show more

Keywords: Pedalling technique, kinetics, biomechanics, performance

DOI: 10.3233/IES-130510

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 203-209, 2013

Authors: Alemdaroğlu, Utku | Dündar, Uŭur | Köklü, Yusuf | Aşci, Alper | Findikoğlu, Gülin

Article Type: Research Article

Abstract: OBJECTIVE: To compare the order effect of a combination of plyometric and resistance training sessions on isokinetic leg strength and vertical jump performance in undergraduate students over the course of a 6-week training program. METHODS: Twenty-four undergraduate volunteers were randomly divided into 3 groups, each group consisting of 3 female and 5 male students. The first group performed traditional combination training (TC; n=8) involving plyometric training exercises at the beginning of a workout session …before resistance exercises; the second group performed contrast training (CT; n=8) involving alternating resistance exercises with plyometric training from set to set; the third group performed complex training (CP; n=8), another form of combination training that involves the planning of several sets of resistance training repetitions, followed by plyometric exercises [16]. All groups completed a similar volume and intensity of training. RESULTS: While all programs produced gains in vertical jump performance (p < 0.01) and isokinetic leg strength (p < 0.01, p < 0.05) except for quadriceps 60°/s for both legs in both genders, no between group differences were observed for any performance value. CONCLUSIONS: The use of plyometric and resistance training within the same training session can be used interchangeably, irrespective of exercise order and gender. Show more

Keywords: Power, plyometric training, resistance training, isokinetic leg strength, vertical jump

DOI: 10.3233/IES-130509

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 211-217, 2013

Authors: Moço, Vanessa J.R. | Lopes, Agnaldo J. | Vigário, Patrícia S. | Almeida, Vivian P. | Dias, Renato F. | Menezes, Sara L.S. | Guimarães, Fernando S.

Article Type: Research Article

Abstract: BACKGROUND: Although there is some evidence that the progression of lung disease associated with protein malnutrition and metabolic impairments contribute to muscle mass atrophy and dysfunction, the causes of exercise limitation in patients with Cystic Fibrosis (CF) are still poor understood. OBJECTIVE: The primary aim of this study was to characterize the functional aspects of CF adult patients. Secondarily, we aimed to evaluate the association between pulmonary function, nutritional status and functional …capacity variables. METHODS: In a cross-sectional study, twenty-one adult patients with CF underwent spirometry, whole-body plethysmography, carbon dioxide diffusion capacity, bioelectrical impedance analysis, cardiopulmonary exercise testing (CPET), six-minute walk test (6MWT) and quadriceps maximal isometric strength and endurance. According to data distribution (Shapiro-Wilk test), statistical analysis used Student's t-test or Mann-Whitney test for comparisons, and Pearson's test for correlations. The significance level was set at 5%. RESULTS: The patients presented with reduced peak VO_{2} , distance in the 6MWT (6MWD), fat-free mass, peripheral and respiratory muscle strength, and quadriceps endurance. There were associations between pulmonary function variables and the results of exercise tests (CPET and 6MWD), as well as between static hyperinflation and CPET variables, and peripheral muscle function (force and endurance) and 6MWD. CONCLUSIONS: Adult patients with CF have impaired exercise tolerance, nutritional status, and peripheral muscles' strength and endurance. There are associations between exercise capacity, pulmonary function and skeletal muscles' performance in these patients. Show more

Keywords: Exercise test, exercise tolerance, cystic fibrosis, respiratory function tests, muscle fatigue

DOI: 10.3233/IES-130508

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 219-226, 2013

Authors: Hébert-Losier, Kim | Willis, Sarah J. | Holmberg, Hans-Christer

Article Type: Research Article

Abstract: OBJECTIVE: To characterize the reproducibility of three indicators of fatigue (FIs) specific to concentric plantar-flexion isokinetic testing at knee flexion (KF) angles of 0° (straight) and 45° (bent). METHODS: On two separate days one week apart, thirty-four males performed 50 consecutive maximal concentric isokinetic plantar-flexion contractions at 60°/s with 0° and 45° of KF. Differences in the pre- and post-maximal voluntary isometric contraction torques (FI_{static} ), powers during the initial five and last five …isokinetic contractions (FI_{dynamic} ) and powers during the 50 isokinetic contractions (FI_{slope} ) were used as FIs. Changes in means, intra-class correlation coefficients (ICCs) and coefficients of variations (CVs) were computed to quantify the reproducibility of the FIs. Comparisons were made between the two KF angles and three FIs using two-way repeated measures ANOVA. RESULTS: For both KF angles and three FIs, ICCs ranged from 0.52 to 0.71 and CVs from 10.0 to 29.3%. The CVs from the two isokinetic-based FIs were lower than those from the isometric FI and a trend towards larger ICCs at 0° was observed. CONCLUSIONS: The reproducibility of the three FIs was not sufficient to be termed 'acceptable'. The FI_{slope} and FI_{dynamic} were more reproducible than FI_{static} and are recommended – with the knee straight rather than bent – until more reliable indicators become available. Show more

Keywords: Ankle, endurance, IsoMed2000-dynamometer, lower extremity, musculoskeletal, test-retest reliability, triceps surae muscle

DOI: 10.3233/IES-130507

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 227-236, 2013

Authors: Kim, Jae-Deung | Oh, Hye-Won | Lee, Jung-Hyun | Cha, Jun-Youl | Ko, Il-Gyu | Jee, Yong-Seok

Article Type: Research Article

Abstract: BACKGROUND: Effectiveness of inversion traction has been revealed in patients with chronic low back pain (CLBP), however, it is still unknown as to which angles of inversion traction positively affect patients with CLBP. OBJECTIVE: To investigate the angle-effects of inversion traction on pain sensation, lumbar flexibility, and trunk muscles (flexors and extensors) strength in patients with CLBP after an 8 week treatment program. METHODS: Forty-seven women suffering nonspecific CLBP for 23.00 ± 5.45 weeks were included prospectively …and randomized into 3 groups: supine group (SG; n=15), inversion −30° group (I30G; n=18), and inversion −60° group (I60G; n=14), respectively. Each group completed a 3-minute × 3-set inversion traction protocol at 0°, inverted −30°, or inverted −60°, respectively for 4 days a week during 8 weeks. The outcome measures included rating of pain using the visual analogue scale (VAS), flexibility of lumbosacral joint, and the isokinetic strength of the trunk flexors and extensors at 60°/s. RESULTS: Pain was significantly improved after 8 weeks. The reductions observed in VAS scores were lower in the I60G compared with the changes in I30G and SG. Significant interaction effects were observed in trunk flexion and extension particularly in the I60G condition. There was also a significant increase in the extensor peak torque of the I60G. CONCLUSIONS: Inversion traction at angle of −60° reduced back pain or discomfort and improved lumbar flexibility and isokinetic trunk extensor strength in patients with CLBP following an 8 week program. Therefore, this treatment modality may be suitable for patient groups of similar CLBP phenomenology. Show more

Keywords: Back pain, trunk flexor, trunk extensor, lumbar flexibility

DOI: 10.3233/IES-130506

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 237-246, 2013

Authors: Hismiogullari, Adnan Adil | Punduk, Zekine | Hismiogullari, Sahver Ege | Yavuz, Ozlem

Article Type: Research Article

Abstract: BACKGROUND: Commercial energy drink usage is reported to be higher in athletes and adolescents. However, the impact of pre-exercise consumption of energy beverages on hematologic and biochemical responses and skeletal muscle contractile properties has not been fully elucidated. METHOD: Ten male subjects performed 50 maximal eccentric actions on an isokinetic dynamometer at 90°/sec followed by two identical trials that were preceded by consuming either a placebo (P) or energy drink (ED) beverage. The test was …repeated after 7–10 days while consuming the alternate beverage. Complete blood counts and chemistry profile was conducted before and immediately after exercise. RESULTS: Eccentric contractions resulted in an increased number of neutrophils (Neut) and decreased lymphocytes (Lymph), decreased eosinophils (EOS) and did not change basophil (BASO) levels in control. However, the BASO levels increased immediately after the exercise with P and ED beverage consumption. In contrast, P and ED beverage consumption had no effect on Neut, Lymph, MONO or EOS counts after exercise compared to pre-exercise values. Acute exercise increased creatinine kinase (CK) and decreased phosphorus (Pi) but did not have any effect on other blood chemistry parameters. The biochemical profile and eccentric muscle contractile properties were not significantly affected by any of the beverages. CONCLUSIONS: Consumption of pre-exercise energy drink does not have a favorable effect on immune blood cells induced in the acute eccentric exercise model. Show more

Keywords: Eccentric contractions, energy drink, hematologic parameters, biochemical parameters

DOI: 10.3233/IES-130505

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 247-252, 2013

Authors: Jenkins, Nathaniel D.M. | Palmer, Ty B. | Cramer, Joel T.

Article Type: Research Article

Abstract: BACKGROUND: The rate of torque development (RTD) and the rate of velocity development (RVD) have previously been described as related; however, a direct comparison has not been performed. OBJECTIVE: The purposes of this study were to compare voluntary and evoked RVD and RTD during the same maximal isokinetic leg extensions muscle actions and to indirectly explore the influence of motor unit discharge frequency on these variables. METHODS: Sixteen men completed three maximal voluntary and three …maximal evoked isokinetic leg extension muscle actions at 60°·s^{-1} . Peak RVD, general RVD, peak RTD, and electromechanical delay (EMD) were calculated from the voluntary and evoked muscle actions. Voluntary and evoked RTD and RVD were also calculated for each 10 ms epoch up to 200 ms of the muscle actions. RESULTS: There was no interaction between voluntary and evoked RVD across time (p=0.12), but there was an interaction for RTD (p<0.01). However, peak RTD occurred prior to the isokinetic load range. Peak RTD (p<0.001), peak RVD (p< 0.01), general RVD (p< 0.01), isokinetic load range (p<0.001), EMD (p<0.001), and PT (p<0.001) were greater for voluntary than evoked muscle actions, which was expected due to the influence of voluntary motor unit firing rates. CONCLUSIONS: Overall, these results suggested that the calculation of RTD during the acceleration phase of an isokinetic muscle action may not be valid due to the unknown load and increasing velocity. Furthermore, the RVD may be influenced by motor unit firing rate, but to a lesser extent than RTD. Show more

Keywords: Involuntary, explosive neuromuscular characteristics, electrical stimulation, rapid force production, acceleration range of motion

DOI: 10.3233/IES-130504

Citation: Isokinetics and Exercise Science, vol. 21, no. 3, pp. 253-261, 2013