bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromyography and high-speed elbow flexor exercise
Authors: Davidson Mark E. , Shepherd Catherine M. , Biga James , Davison Steve W. , Giebel Rachel M. , Charles Jessica L. , Learmonth Lexis A. , Caruso John F.
Published: October 2018

Our study assessed motor unit behavior and muscle function from high-speed unilateral elbow flexor workouts. Electromyography and performance data were obtained from subjects who completed three workouts on an Impulse(Impulse Training Systems; Newnan, GA) exercise machine. Comprised of both tonic and phasic repetitions, workouts were done with three different loads(1.13, 3.4 and 6.8 kg) added to the machine. Electromyography was measured from three muscles (biceps brachii, triceps brachii, brachioradialis). Dependent variable means, obtained as the elbow flexed and extended, were compared with 2(tonic, phasic) x2 (men, women) x3 (1.13, 3.4 and 6.8 kg) ANOVAs, with repeated measures for repetition and load. Bonferroni's adjustment preserved family-wise error rates and t-tests served as a post-hoc. With α=0.05, several dependent variables displayed intra-repetition and -load effects. However triceps root mean square (RMS) values displayed repetition x load interactions for both elbow flexion and extension. The triceps, an elbow flexion antagonist, may act as an important joint stabilizer, particularly at faster velocities and more extended joint angles. Unlike isometric or standard low-velocity paradigms performed against heavy loads, high-speed exercise may entail a more equitable distribution among factors (motor unit recruitment, rate coding, reflex potentiation, antagonist co-contraction) responsible for current triceps RMS values.
Isokinetic strength of the trunk flexors and extensors in ankylosing spondylitis
Authors: Durmus Bekir , Sahin Nilay , Baysal Ozlem , Ersoy Yuksel , Baysal Tamer , Koca Tuba Tulay , Altay Zuhal
Published: October 2018

BACKGROUND: Objective measurement of trunk muscles strength in ankylosing spondylitis (AS) may provide clinical information that can be used to evaluate functional disability.

OBJECTIVE: To compare the isokinetic strength of trunk muscles in AS patients with healthy subjects.

METHODS: Thirty-four patients with AS and thirty-one healthy subjects were enrolled. Patients with spinal ankylosis and bridged syndesmophytes in the lumbar and dorsal vertebrae were excluded. Trunk flexor and extensor strength was measured at: 60 and 90°/sec.

RESULTS: When compared with the control group, AS patients demonstrated 38% and 24% decrease in the extensor and flexor strength, respectively (p< 0.05). In addition, the flexor/extensor strength ratio was 1.0 and 0.8 in the patients and control subjects, respectively.

CONCLUSIONS: In view of the relatively selective extensor weakness we recommend assessment of trunk muscle strength in these patients for guiding clinicians regarding possible reconditioning exercises in the early period of AS.
Pulmonary disease severity and peripheral muscle function as limiting factors for exercise capacity in adult patients with cystic fibrosis
Authors: Moço Vanessa J.R. , Lopes Agnaldo J. , Vigário Patrícia S. , Almeida Vivian P. , Dias Renato F. , Menezes Sara L.S. , Guimarães Fernando S.
Published: October 2018

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.
The effect of exercise order incorporating plyometric and resistance training on isokinetic leg strength and vertical jump performance: A comparative study
Authors: Alemdaroğlu Utku , Dündar Uŭur , Köklü Yusuf , Aşci Alper , Findikoğlu Gülin
Published: October 2018

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.
Strength enhancement with limited range closed kinetic chain isokinetic exercise of the upper extremity
Authors: Cale'-Benzoor Maya , Dickstein Ruth , Arnon Michal , Ayalon Moshe
Published: October 2018

BACKGROUND: Specificity plays an important role in the design of strength training protocols. One of the paramount factors is the range of motion (ROM).

OBJECTIVE: To explore limited range of motion (ROM) strength training using a closed chain upper extremity push pull motion. Range specific effects and transferability (strength gains outside the trained ROM) were investigated.

METHOD: 45 healthy women (18–50 ± 4.2) randomly assigned to one of three groups: Full ROM group, Limited ROM group, Control group. Training and testing were conducted using a closed chain attachment of an isokinetic dynamometer, at a constant linear velocity of 12.22 cm/s(corresponding to the dynamometer angular velocity of 60°/sec) and a second condition of 36.67 cm/s (corresponding to the dynamometer angular velocity of 180°/sec). Training lasted 6 weeks X 2 days per week, through either full or limited ROM, representing a middle segment of the linear displacement of the handle through the full ROM. Peak force and work data were evaluated.

RESULTS: Significant gains in peak force and work values at full ROM and all sub ranges were noted for both training groups. Transferability of strength was demonstrated for limited ROM training, whereas specificity could be demonstrated only under the condition of range X velocity interaction.

CONCLUSION: Our findings support the use of limited ROM training in the upper extremity and are in agreement with previous data regarding the knee extensors. Limited ROM training may be used early on in upper extremity rehabilitation. Particularly, the suggested protocol may be safely applied to scapular rehabilitation.
Asymmetrical trunk muscle activities and kinematics during dominant and nondominant leg lifts in subjects with lumbar rotation with flexion syndrome
Authors: Yoon Tae-Lim , Cynn Heon-Seock , Choi Sil-Ah , Choi Woo-Jeong , Lee Ji-Hyun
Published: October 2018

BACKGROUND: Patients with lower back pain due to lumbar rotation with flexion syndrome (LRFS) have greater asymmetry of rotation in the lumbopelvic region than healthy people.

OBJECTIVE: To understand the activities of the trunk muscle and kinematics of the trunk and pelvis in patients with LRFS during the bird-dog (BD) exercise with dominant non-dominant leg lifts, a frequently prescribed stabilization exercise.

METHODS: We compared activity and kinematics during the BD exercise with dominant and non-dominant leg lifts in 11 patients (6 male, 5 female) with LRFS who were recruited from a university.

RESULTS: Significantly lower activation of the ipsilateral erector spinae muscle was found during the nondominant leg lift than the dominant leg lift in patients performing the BD exercise (t =−3.71, p=0.04). In addition, the trunk was significantly flexed during the dominant leg lift (t=−6.069, p=0.00) and bent to the right side(t=3.131, p=0.01) during both dominant and nondominant leg lifts.

CONCLUSIONS: These results imply the presence of asymmetrical muscle activity and kinematics in the trunks of subjects with LRFS. This information should be considered for prescribing exercises to such subjects.
Do compression sleeves worn during exercise affect muscle recovery?
Authors: Pereira Maria C. , Bottaro Martim , Brown Lee E. , Rocha-Junior Valdinar A. , Martorelli Saulo S. , Nóbrega Otavio T. , Souza Vinicius C. , Pinto Ronei S. , Carmo Jake
Published: October 2018

BACKGROUND: Athletes often wear compression sleeves, yet studies on their effects are lacking.

OBJECTIVE: The aim of this study was to determine the effect of compression sleeves worn during exercise on muscle recovery following exercise.

METHODS: Twenty-two resistance trained men were randomly assigned to either a compression sleeve (GCS, n=11) or placebo sleeve (GPS, n=11) group. They performed 4 sets of 10 isokinetic eccentric/concentric elbow flexion repetitions. Isometric peak torque, muscle activation, echo intensity and perceived muscle soreness were measured at baseline, immediately after and 24, 48, 72 and 96∼hours post exercise. Blood CK samples were obtained at baseline, 48 and 96 hours post exercise.

RESULTS: There were no significant interactions or main effects for group regarding any of the variables (P > 0.05). There were main effects for time for all variables except muscle activation. Isometric peak torque immediately after and 24, 48, 72 and 96 hours were all significantly less than baseline. Echo intensity immediately after was significantly greater than baseline. Perceived muscle soreness at 48 h was greater than baseline. CK levels at 48 and 96 hours were greater than baseline.

CONCLUSIONS: The use of compression sleeves is not recommended for the alleged enhancement of muscle recovery following upper body high-intensity exercise in young resistance-trained men.
Cyclists and triathletes do not differ in muscle volume, muscle recruitment or pedal force effectiveness
Authors: Lanferdini Fábio J. , Jacques Tiago C. , Bini Rodrigo R. , Vaz Marco A.
Published: October 2018

BACKGROUND: Non-specific adaptation from training can elicit similar muscle volume and muscle activation between cyclists and triathletes which differ in comparison to non-athletes.

OBJECTIVE: To compare muscle volume, muscle activation and pedal forces of cyclists, triathletes and non-athletes.

METHODS: Twelve cyclists, ten triathletes and twelve non-athletes performed an incremental test to determine their maximal power output(PO _{MAX} ). Quadriceps and triceps surae volume were estimated from ultrasound images taken at rest, while pedal forces and muscle activation were recorded at PO _{MAX} at 90 rpm.

RESULTS: Quadriceps volume was larger in cyclists (∼22%, p< 0.04) and triathletes (∼40%, p< 0.01) compared to non-athletes. Higher activation of rectus femoris (∼55%, p=0.01) and tibialis anterior(∼88%, p=0.01) were observed for triathletes compared to non-athletes at the first quarter of the pedaling cycle. Triathletes also showed higher activation for tibialis anterior than cyclists (∼68%, p=0.03) at the first quarter. Non-athletes applied greater force on the pedal compared to triathletes at the first quarter (∼42%, p< 0.01). Pedal force effectiveness was higher for athletes (37–44%, p< 0.02) compared to non-athletes at the fourth quarter.

CONCLUSIONS: Similar muscle volume and muscle activation between cyclists and triathletes may be related to a similar training volume supporting differences relative to non-athletes.
ß-Alanine's impact on exercise and blood lactate values incurred from repetitive supramaximal activity
Authors: Caruso John , Barbosa Amanda , Perry Rachel , Edwards Roman , Erickson Lacey , Potter William , Keller Michael
Published: October 2018

BACKGROUND: ß-Alanine aids exercise performance by increasing intracellular carnosine content. Added carnosine should buffer more H ^{ +} produced from exercise and evoke a higher blood lactate concentration([BLa ^{ - } ]) before a person succumbs to fatigue.

OBJECTIVE: With a within-subjects design, we compared the effects of placebo (maltodextrin) andß-alanine administrations on [BLa ^{-} ] and average power (AP) values derived from repetitive bouts of lower body supramaximal activity.

METHODS: Over separate 30-day periods, sedentary subjects (n=10) ingested placebo, followed by ß-alanine (3 g ˙ day ^{-1} ), capsules. After each period, subjects performed two four-set leg press workouts. [BLa ^{-} ] values were measured before, and zero-, five-, ten, 15- and 20-minutes post-exercise. [BLa ^{-} ] data underwent a 2 × 6 ANOVA, with repeated measures per independent variable. AP values were compared with a 2× 4 ANCOVA, with repeated measures per independent variable.

RESULTS: AP and [BLa ^{-} ] results each included a two-way interaction. ß-alanine elicited higher set two and four AP values versus the corresponding placebo values. [BLa ^{-} ] values at zero-minutes post-exercise were significantly higher from ß-alanine, versus the placebo, treatment.

CONCLUSIONS: Greater AP and [BLa ^{ - } ] values fromß-alanine suggest exercise likely was able to proceed to a greater extent without increasing intracellular acidosis due to a heightened buffer capacity.
Velocity Spectrum Study of Knee Flexion and Extension in Normal Adults: 60 to 500 deg/sec
Authors: Hall Pamela S. , Roofner Marilyn A.
Published: October 2018

The purpose of this study was to examine normative data for uninjured adults when tested isokinetically over a velocity spectrum. Sixty adults, 30 males and 30 females, between the ages of 20 and 62, were tested for quadriceps femoris and hamstring peak torque, quadriceps femoris peak torque/body weight ratio, quadriceps femoris average work, quadriceps femoris average power, and quadriceps femoris angle of peak torque. Subjects were tested at 60, 180, 300, 400, and 500 deg/sec. Mean isokinetic values versus speed were determined for both males and females to allow visual analysis of the change in these parameters over the velocity spectrum. Personal data, including reported weekly exercise regimen, were assessed using Pearson correlation coefficients to analyze any association among demographic factors and isokinetically produced values at 180 deg/sec. Finally, a regression analysis was used to formulate an equation to predict peak torque, average work, and average power for the right quadriceps femoris at 180 deg/sec.
Reliability of Isokinetic Concentric Closed Kinematic Chain Testing of the Hip and Knee Extensors
Authors: Levine David , Klein Aimee , Morrissey Matthew
Published: October 2018

The purpose of this study was to assess the intratester reliability of torque variables of the hip and knee extensor musculature during an isokinetic, concentric contraction in a closed kinematic chain. Nineteen healthy subjects (10 females, 9 males, mean age 24 ± 4) were tested on the Kin-Com on two occasions, exactly 1 wk apart. The subjects were stabilized in the supine position with their dominant foot fixed to a foot plate, in approximately 115 deg of hip and knee flexion, and asked to extend to full hip and knee extension. Testing was performed at 30, 120, and 210 deg/sec. Reliability was determined on the female group (n = 10), the male group (n = 9), and the combined group (n = 19). Torque measurements of the hip and knee extensors in a closed kinematic chain using this protocol were reliable except for the male group at 30 deg/sec. The intraclass correlation coefficients (lCCs) for combined group torque values were comparable to those of previous studies performed on the knee extensors in an open kinematic chain. These results indicate that isokinetic concentric testing of the hip and knee extensors in a closed kinematic chain can be reliable when this protocol is used.
Preliminary Clinical Evaluation of the Breg K.A.T.: Effects of Training in Normals
Authors: France E. Paul , Derscheid Gary , Irragang Jay , Malone Terry , Petersen Roger , Tippett Steve , Wilk Kevin
Published: October 2018

A multicenter study was conducted to characterize the effects of balance therapy using the Kinesthetic Ability Training (KAT.) balance board on static balance in healthy, uninjured individuals. The results of this preliminary study demonstrated that individuals who participated in a balance training group were able to improve their static balance ability after a six-week training period in comparison to a control group.
Reliability of peak torque values for concentric and eccentric shoulder internal and external rotation on the biodex, kinetic communicator, and lido dynamometers
Authors: Kimura Iris F. , Gulick Dawn T. , Alexander Deborah M. , Takao Scott H.
Published: October 2018

The purpose of this study was to investigate the concentric and eccentric peak torque reliability of the Biodex B-2000, Kinetic Communicator, and Lido isokinetic dynamometers when testing the shoulder internal and external rotators. The subjects were 22 males with no previous shoulder pathology. Each subject completed two test sessions for each isokinetic dynamometer. The right upper extremity was tested at 120°/s through a 140° arc of motion with the shoulder in 90° of abduction. After a warm-up of three sub-maximal repetitions and 1 maximal repetition, five maximal repetitions were completed in either the concentric or eccentric mode. A 5-min rest period lapsed and then the second test mode was completed. Six days later, the subjects were tested in the reverse order. This procedure was completed for each isokinetic dynamometer. Four one-way analyses of variance with repeated measures were used to compare peak torque values of shoulder internal and external rotation in each test mode. The F-values indicated significant differences in concentric and eccentric internal rotation and eccentric external rotation. Therefore indicating that comparisons of peak torque values should not be made between different isokinetic dynamometers. Means, standard error of measurement (SEM), and intraclass correlations (ICC) were calculated for each dynamometer in each test mode. The ICCs for concentric peak torque were generally higher than those of eccentric peak torque, but lower than those reported by previous researchers. Of the many variables that can impact isokinetic testing, position may have been the most influential in this study. It is possible that impingement of the shoulder rotators occured with the shoulder in 90 of abduction. Perhaps another test position would have yielded more consistent results. The presence of delayed onset muscle soreness may have also influenced this study. Copyright
The effects of patellar bracing on quadriceps EMG activity during isokinetic exercise
Authors: Gulling Larry K. , Lephart Scott M. , Stone David A. , Irrgang James J. , Pincivero Danny M.
Published: October 2018

Patellofemoral pain syndrome is a prevalent ailment experienced by a number of individuals participating in regular physical activity. Little information is available concerning the effects of patellofemoral bracing on the function of the extensor mechanism in patellofemoral malalignment patients. The purpose of this study was to examine the effects of patellar bracing on the extensor mechanism in relation to isokinetic exercise. Sixteen subjects exhibiting patellofemoral pain symptoms were tested on an isokinetic dynamometer with and without a patellofemoral brace. The testing procedure involved three maximal concentric/eccentric quadriceps contractions at an angular velocity of 180°/s. Electromyographic (EMG) activity of the vastus medialis obliqus (VMO) and the vastus lateralis (VL) were recorded during testing. Integrated EMG activity (IEMG) was analyzed by a three-way ANOVA with repeated measures (p < 0.05). The results indicated that the application of the patellar brace resulted in a significantly smaller IEMG signal than during the non-braced condition in both the VMO and VL during both concentric and eccentric contractions (P < 0.05). The IEMG signal of the VMO was found to be significantly greater than the VL regardless of test or brace condition (P < 0.05). Moreover, the IEMG signal was also found to be significantly greater during the concentric contractions than the eccentric contractions during all testing conditions (P < 0.05). The clinical implication from this study suggests that muscle activation of the VMO and VL were reduced with the use of the brace. This type of bracing may provide mechanical support to the patellofemoral joint as evidenced by the reduction in quadriceps activation during isokinetic knee extension exercise.
Validity study of a novel test protocol for the identification of submaximal muscular effort
Authors: David Guy , Dvir Zeevi , Mackintosh Shylie , Brien Chris
Published: October 2018

The purpose of this study was two-fold: (a) to further examine the efficiency of a novel protocol for differentiating maximal from submaximal effort of the knee extensors; and (b) to test the effect of effort performance order: maximal-submaximal vs. submaximal-maximal on the outcome, namely analyze an aspect of internal validity of the protocol. Thirteen women and 17 men took part in the study. They were randomly assigned to one of two groups. Group 1 performed a set of four intermittent maximal (MAX) concentric-eccentric contractions at 30 and 180°/s which was followed by an identical set but at a submaximal level. In the latter set, subjects were asked to exert a submaximal level of force they could best reproduce (BREP). Group 2 performed the same sets but in a reverse order. Results have indicated: (1) no significant differences between the groups, hence prior exposure to maximal effort did not affect the differentiating capacity of the protocol; (2) no significant differences between absolute variability of the MAX and BREP conditions; (3) the DEC parameter defined as the difference in the eccentric/concentric force ratios at the high and low test velocities was highly effective (P < 0.001) in differentiating the MAX from the BREP conditions.
Influence of Age on Calf Muscle Length and Passive Stiffness Variables at Different Stretch Velocities
Authors: Gajdosik Richard L.
Published: October 2018

This study examined the influence of age on calf muscle length and passive stiffness variables at different stretch velocities. Ten younger aged men (31 [SD 6] years), nine middle aged men (48 [SD 6] years), and nine older aged men (70 [SD 6] years) were tested using a KIN-COM 500R dynamometer. The right calf muscles were stretched from relaxed plantar flexion to maximal passive dorsiflexion at four randomly ordered velocities of 5°·s−1, 30°·s−1, 60°·s−1 and 120°·s−1 with negligible surface EMG activity (< 0.05 m V) in the calf muscles at all velocities. The maximal passive dorsiflexion angle, maximal passive torque, initial passive angle (defined at 20% of the maximal passive torque), angular change, and passive stiffness ratios (Δ torque/ Δ angle) through the defined range of motion (ROM) and through the last 10° of ROM were analyzed with ANOVA procedures. The maximal passive dorsiflexion angle decreased as age increased (P<0.05). The maximal passive torque increased as the velocity of stretch increased (P<0.001) and velocity of stretch interacted significantly with the age groups (P<0.01); the older men had less maximal passive torque at 60°·s−1 and 120°·s−1 (P<0.05). The passive stiffness ratios through the defined ROM showed a significant effect of stretch velocity (P<0.01). Within the last 10° of dorsiflexion ROM the ratios showed a significant effect of group (P<0.05), stretch velocity (P<0.001), and interaction (P<0.001). For the younger and middle aged men the passive stiffness increased as the stretch velocity increased, but for the older men the passive stiffness decreased as the stretch velocity increased, perhaps influenced by muscle atrophy, changes in muscle fiber type and changes in the amount of adipose tissue. The results indicated that decreased calf muscle length was associated with decreased maximal passive torque and decreased passive stiffness for older men beyond 60 years of age.
Knee extensor strength 12 and 18 weeks post anterior cruciate ligament reconstruction
Authors: Strauss G.R. , Bozikovic A.J. , Jones G.L. , Neale G.C. , Spittles M.R. , Boyle J.J.W.
Published: October 2018

The aim of this study was to determine if a deficit existed in the truncated range average torque (TRAT) values of the knee extensor muscles of the operated limb in subjects with patellar tendon autograft anterior cruciate ligament reconstructions when compared with the non-operated limb at 12 and 18 weeks following surgery. Subjects were assessed using the Kin-Com (500 H) dynamometer utilising a proximal pad to reduce shear force through the tibio-femoral joint. Three isokinetic velocities (60, 120 and 180 deg/sec) for concentric and one velocity (60 deg/sec) for eccentric muscle actions were tested. Results of the TRAT for knee extensors showed average concentric deficits of 25.4% at 12 weeks and 17.6% compared to the non-operated limb on both testing occasions. There was a significant improvement of TRAT scores of the operated limb from 12 to 18 weeks for all testing velocities except 120 deg/sec. The results of this study not only provide quantitative values of knee extensor strength deficits at 12 and 18 weeks post-surgery but also indicate a significant improvement in knee extensor strength of the operated limb over the same time period. This confirms both the large strength deficits and improvements in strength which clinicians have long suspected exist at this early stage following reconstructive surgery.
Unpredictable error in dynamometry measurements: a quantitative analysis of the literature
Authors: Keating Jennifer L. , Matyas Thomas A.
Published: October 2018

This research investigated factors influencing unpredictable variability in dynamometric measurements. The criterion for inclusion in this review was that the standard error of measurement (SEM) associated with test procedures could be estimated. SEMs were determined using reported retest correlations and standard deviations of measurements. Subject factors found to influence variability were impairment and gender. Test factors implicated were movement direction and test speed. A strong relationship was indicated between score magnitude and variability. SEMs derived from measurements of low scoring subjects do not appear appropriate for interpreting measurements of higher scoring subjects. Measurements of subjects who achieve higher dynamometry scores appear more variable than measurements of lower scoring subjects. Similarly, as test conditions facilitate higher scores eg lower test speeds, variability in measurements increases. SEMs employed by clinicians to interpret test results should be derived from a population with a mean measurement that is representative of the subject being tested.
The effects of body position and stabilization on isokinetic torque ratios for the shoulder rotators
Authors: Hartsell H.D.
Published: October 2018

Body position and stabilization is a controversial issue for shoulder rotational testing in the scapular plane. The purposes were to determine the effects of body position on the external/internal rotation(ER/IR) ratios and how closely they approximated previously reported ratios. Twenty-two healthy, informed subjects participated in test-retest isokinetic sessions involving two body positions (seated, standing), two rotational joint motions (external,internal), three velocities (60,120,180 dgs) and two contraction types (concentric, eccentric). Intraclass correlation coefficients ranged from 0.89--0.93. A three-way ANOVA with repeated measures, used to analyze the data for contraction type separately, showed significant effects (p< 0.000) for body position regardless of body position. Concentrically, significant effects were observed for gender (p<0.018), velocity (p < 0.000) and body position x velocity x gender (p < 0.003). It was concluded that use of the standing position with adequate stabilization is viable and perhaps more applicable to activities of daily living. Secondly, the `acceptable' ER/IR ratios (0.6--0.7) previously defined should be extended to 0.5--0.7 to allow for varying joint and body positioning.
A comparison of iEMG activity between the medial and lateral heads of the gastrocnemius muscle during partial weight bearing plantarflexion contractions at varying loads
Authors: Fiebert Ira M. , Spielholz Neil I. , Applegate Brooks , Crabtree Frederick G. , Martin Laurie A. , Katherine L. Parker I.
Published: October 2018

The purpose of this study was to determine the differences between iEMG activity of the medial head (MH) and lateral head (LH) of the gastrocnemius of normal right legs during partial weight bearing isometric plantarflexion contractions under varying percentages of body weight (BW) and maximal contractions. Fifty-three healthy volunteers ranging in age from 18 to 35, with no history of right lower extremity injury or disease volunteered for this study. Each subject's age, height, weight, and medical history were recorded. A chronaximeter was used to identify the motor points of the MH and LH. After performing a 5-minute warm-up, surface electrodes were placed just distal to the motor point, and subjects were positioned on the sliding board of the Total Gym Therapy System. The percentage of BW used as resistance was determined by the angle of inclination of the slide board. The subjects were then directed to plantarflex to 20 degrees, with 8 second iEMG recordings, with a proprioceptive cue, under four conditions: 30%, isometric (1 trial). Paired $t$ -tests concluded the MH consistently demonstrated a larger percent of total iEMG activity than the LH in the 30, 50, and 70% difference between iEMG activity of the MH and LH during the maximum isometric trial was not statistically significant ( $p=$ 0.2958). A repeated measures ANOVA and post-hoc analysis demonstrated the percent of total iEMG differences to be greater at the lighter loads (D30 $>$ D50 $>$ D70; $p<$ 0.0001). These findings strongly suggest separate but complementary functions of the two heads of the gastrocnemius muscle.
Hamstring muscle tear with recurrent complaints: An isokinetic profile
Authors: Croisier Jean-Louis , Crielaard Jean-Michel
Published: October 2018

The purpose of this study was to determine the isokinetic profile of specialized athletes with previous hamstring tears and recurrent complaints upon return to sports activities, using a Kintrex 500 dynamometer. Twenty-three subjects were examined through a concentric protocol and fifteen of them benefited from a complementary eccentric assessment. Despite the fact that some cases presented normal isokinetic results, the statistical analysis has demonstrated particular features. In reference to the non-involved side performances, the average reduction of peak torque (PT) of the injured muscles surpassed 20% relationship between bodyweight normalized PT and angular velocity demonstrated significant differences in comparison with those of selected non-injured sprinters, most notably in the eccentric sector. A mixed ratio (Flexors $_{\rm eccentric}$ /Quadriceps $_{\rm concentric}$ ) appeared significantly reduced ( $0.75 \pm 0.23$ ) for the injured leg, in comparison with the contralateral non-injured limb ( $0.90 \pm 0.16$ ) and with a control population ( $0.98 \pm 0.14$ ). For the eccentric mode, the angle of peak torque (APT) of the strained muscle occurred in an abnormal articular sector corresponding to a weaker hamstring muscle lengthening than normal. These observations strongly suggest that, among the causative factors, the persistence of muscle strength abnormalities gives rise to recurring hamstring injuries.
Comparing isometric and isokinetic peak strength values using slow speeds on a Cybex 340 isokinetic dynamometer machine
Authors: Burkett Lee N. , Alvar Brent , Irvin Jim
Published: October 2018

The purpose of this research was to compare isometric values(0 $^{\circ}$ s $^{-1}$ ) with isokinetic values generated at slow speeds(12 $^{\circ}$ s $^{-1}$ , 30 $^{\circ}$ s $^{-1}$ and 60 $^{\circ}$ s $^{-1}$ ) based on measurement of 40 college males. A one-way ANOVA indicated a significant difference with respect to speeds ( $F_{3,148} = 13.10$ , $p<0.01$ ). A post hoc analysis showed that all speeds were significantly different from each other. The greatest average maximal hamstring strength values were produced with isometric(0 $^{\circ}$ s $^{-1}$ ) contractions and the least average maximal hamstring strength at 60 $^{\circ}$ s $^{-1}$ . It is suggested that if a true absolute maximal hamstring strength test is desired for the hamstring musculature one should use a speed of 0 $^{\circ}$ s $^{-1}$ . Regression analysis indicated that a speed of 12 $^{\circ}$ s $^{-1}$ produced the best regression equation. It is suggested that, the term peak strength rather than maximum strength should be used for speeds greater than 0 $^{\circ}$ s $^{-1}$ .
Pubertal children are unable to relax during the passive gravity correction procedure on the isokinetic dynamometer
Authors: Kellis Eleftherios
Published: October 2018

One of the most important assumptions of the passive method of gravity correction in isokinetic dynamometry is that subjects are relaxed during the test. The purpose of this study was to examine the validity of the passive gravity correction method in pubertal children. Fifteen pubertal males performed passive knee extensions and flexions at 30°·s $^{-1}$ . The electromyographic (EMG) activity of the vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) was recorded using bipolar surface electrodes. The GM was estimated using five different methods: the recorded GM during knee extension and flexion, the estimated GMs from the recorded knee extension and flexion GMs at 30° of knee flexion and the GM estimated using anthropometric data. The results indicated that the passive knee movements resulted in significantly (p<0.05) higher GM compared to those estimated using anthropometric data or mathematically using the GM at 30°. The GM in the range of 31--90° was significantly (p<0.05) higher during knee extension compared with knee flexion. The VM and VL raw EMGs were significantly (p<0.05) higher during knee extension compared to knee flexion movement, reaching 40% of the their maximum EMG values. The BF EMG ranged from 7% to 10% of the maximum, but it was not significantly different between extension and flexion phases. It can be suggested that the recorded dynamometer moment during passive gravity correction tests is affected by forces exerted by musculotendinous structures which are activated during the test. The application of passive gravity correction techniques in pubertal children demonstrates significant problems and should be applied with extreme caution.
Isokinetic measurements using short range of motion: A new approach to the assessment of muscle function
Authors: Dvir Zeevi
Published: October 2018

Article without abstract.
Proposal for the assessment protocols for different shoulder muscle groups
Authors: Forthomme B. , Croisier J.L. , Crielaard J.M.
Published: October 2018

Article without abstract.
Shoulder isokinetic exploration following shoulder rotator cuff suture
Authors: Binet J. , Forthomme B. , Bierlaire J.P. , Meurant P. , Crielaard J.M. , Croisier J.L.
Published: October 2018

Article without abstract.
A new approach to evaluation of mutiple sclerosis by isokinetic device
Authors: Rochcongar P. , Robineau S. , Nicolas B. , Gallien P. , Durufle A. , Pitrelli S. , Edan G.
Published: October 2018

Article without abstract.
Determination of isokinetic muscle strength in chronic heart failure patients and in patients with chronic obstructive pulmonary disease
Authors: Degache F. , Costes F. , Calmels P. , Garet M. , Barthelemy J.C. , Roche F.
Published: October 2018

Objective: To evaluate the relationship between isokinetic strength, and aerobic aptitude in patients with chronic heart failure (CHF) and with chronic obstructive pulmonary disease (COPD). Methods: Seventeen stable CHF(n=11) and COPD (n=6) patients aged 51.12 ± 9.95 ys old (15 men, 2 women, CHF patients: NYHA class II: n=8 and III: n=3) underwent a dynamic isokinetic force evaluation of the quadriceps (IsoK) at an angular velocity of 180°s $^{-1}$ , a symptom-limited cardiopulmonary exercise test with simultaneous monitoring of respiratory gases, and a 6-min walking test. Body composition was assessed by electrical bioimpedance. The relationships between muscle strength, maximal aerobic performance, results of endurance tests and anthropometric datas were assessed by simple regression analysis. Results: The isokinetic evaluation has been successfully performed in all patients. No cardiac arrhythmic event nor abnormal haemodynamic response was observed in either group of patients. In CHF patients, individual quadricipital muscle strength was significantly related to fat-free mass(r=0.862; p<0.01). However, neither peak O $_2$ (global: r=0.562, p=NS or weight-adjusted: r=0.083, p=NS) nor endurance capacity(r=0.068, p=NS) were significantly related to the peripheral muscle strength. In COPD patients, quadricipital muscle strength was not significantly related to fat-free mass (r=0.242; p=NS) nor any other measured factor. Conclusion: Physiopathological mechanisms of exercise limitation in CHF and COPD patients are complex. Isokinetic strength and O $_2$ peak are not related to each other and are therefore independent. Therefore, a systematic evaluation of isokinetic muscle strength may be of great value. Early degradations in aerobic capacity are probably followed by an alteration in muscle strength.
Isokinetic evaluation of muscular function in patients with chronic pain and fatigability
Authors: Maquet D. , Croisier J.L. , Moutschen M. , Crielaard J.M.
Published: October 2018

Article without abstract.
Short term power output of females during isokinetic cycling
Authors: Williams C.A. , Hammond A. , Doust J.H.
Published: October 2018

Previous studies of short term power output in young people and adults have used cycle ergometers that cannot control cadence or inertial resistance. An innovative isokinetic ergometer has now been designed and the purpose of this study was to investigate the isokinetic short term power output of twelve 15-year-old adolescent girls and nine 21-year-old female adults. Short term power was measured by a power-cadence test and included the calculation of the optimised peak power (PP $_{opt}$ ) and optimal cadence (C $_{opt}$ ) at PP $_{opt}$ . Each subject completed seven maximal sprints, starting at an initial pedal cadence of 90 rev·min $^{-1}$ which after each subsequent five minute rest period, was increased by 10 rev·min $^{-1}$ . Significant differences in absolute PP $_{opt}$ were found between adolescent (624± 985 W) and adult females (740 ± 157 W) respectively (P < 0.05). Significant differences were found in short term power standardised according to leg volume (45.4± 10.8 and 25.8 ± 2.1 W·L $^{-1}$ ) between female adolescents and adults but not according to body mass (P > 0.05). The C $_{opt}$ at PP $_{opt}$ for adolescent females (116 ± 6 rev·min $^{-1}$ ) was not significantly different to adult females (118 ± 13 rev·min $^{-1}$ ). These results add to the scarce amount of isokinetic data on females and provide evidence that age differences in power are not due to cadence dependent factors.
Knee angle does not affect ankle eversion to inversion peak torque ratios derived from an isokinetic dynamometer
Authors: Porter Gary Keith , Kaminski Thomas W.
Published: October 2018

The purpose of this study was to examine varying degrees of knee flexion on isokinetic eversion (E) to inversion (I) strength ratios. Twenty healthy subjects volunteered for this study. Concentric (CON) peak torque (PT) of both ankles (dominant, non-dominant) at three different angles of knee flexion (15°, 30°, 45°) and two different velocities (30°/s, 120°/s) was assessed with ankle plantar flexion maintained at 10°. The E _{CON} :I _{CON} ratios at 30°/s ranged from 0.87 to 1.04 across all three angles, while those at 120°/s ranged from 0.86 to 1.00 indicating no differences in ratios between knee-flexion angles or ankles. However, there was a trend in lower ratios evident in the dominant compared to non-dominant ankles. These results suggest that subjects may be positioned with knee flexion angles ranging from 15° to 45° without influencing the outcome of the ankle eversion and inversion strength measurements.
Analysis of gait differences in healthy runners and runners with chronic Achilles tendon complaints
Authors: Baur Heiner , Divert Caroline , Hirschmüller Anja , Müller Steffen , Belli Alain , Mayer Frank
Published: October 2018

Differences in lower extremity movement characteristics are stated as a reason for overuse injuries. The causal assignment of biomechanical quantities to the onset of complaints is still subject of debate in gait analysis. The purpose of this study was therefore to compare biomechanical gait characteristics by means of plantar pressure distribution (PPD), EMG and ground reaction forces (GRF) in healthy runners and in runners with chronic Achilles tendon complaints (AT). Fourteen healthy runners and 8 runners with AT were examined at 12 km/h. Surface EMG, in-shoe PPD and GRFs were evaluated on a treadmill mounted on force transducers. Subjects ran barefoot and with a reference shoe in random order. EMG time and amplitude quantities, characteristics of the path of the center of pressure (CoP), vertical and a-p forces and impulses were extracted. In AT no differences in CoP-characteristics between barefoot and reference shoe were observed, compared to corresponding significant differences in the control group. Compared to the AT group, the control subjects had a higher activity EMG-amplitudes in the extensor loop during weight acceptance phase, a higher braking impulse and a lower pushing impulse. It is thus concluded that healthy runners differ from AT patients in terms of movement characteristics especially in running.
Time to peak torque for knee and elbow extensors and flexors in children, teenagers and adults
Authors: De Ste Croix M.B.A. , Deighan M.A. , Armstrong N.
Published: October 2018

The aim of this study was to examine the age and sex associated development of time to peak torque (TPT) of the knee and elbow extensors and flexors. 137 subjects participated in this study consisting of three groups aged 9/10 y, 16/17 y and 21+ y. Isokinetic concentric knee and elbow extension and flexion were measured using a calibrated Biodex system 3 and TPT was determined. ANOVA identified significant (p < 0.05) interaction effects for stature and body mass. A main effect for group for knee extension TPT (range 0.20–0.26 s) and elbow flexion TPT (range 0.33–0.40 s) was identified. For elbow flexion the 16/17 y-olds demonstrated significantly faster TPT than the 9/10 y-olds and adults. No significant interaction or main effects for knee flexion (range 0.0.19–0.23 s) or elbow extension (range 0.40–0.44 s) were observed. Pearson product moment correlation coefficients identified no significant relationship between TPT and peak torque for knee and elbow extensors and knee flexors in all groups. A significant negative correlation (p < 0.05) was found for the elbow flexors for both 9/10 y-olds and adults for females but not males. To conclude, no sex differences in TPT of the knee and elbow extensor and flexor muscles were found. Age related changes in TPT appear to be muscle group and muscle action specific and highlight the caution one has to exercise in making assumptions between muscle groups and actions.
The effect of electromyographic equipment on golf swing kinematics
Authors: Egret Claire , Weber Jacques , Dujardin Franck , Chollet Didier
Published: October 2018

Background: EMG equipment is used to measure muscular activity during sports movements. A methodological study is hence necessary to identify how this cumbersome equipment may hinder golfers in performing the golf swing.

Methods: Measurements of kinematic data during swing were conducted using an optoelectronic system. Surface bipolar electrodes with integrated preamplifiers were used to monitor the myoelectric signals during golf swing. Six experienced right-handed male golfers performed six swings with electromyographic equipment fixed on their body and six swings without electromyographic equipment.

Results: There was a significant effect in terms of shoulder joint rotation at maximal backswing (7.7%), in the right elbow flexion at the address (3.7%), at the top of the backswing (3.1%) and in the clubhead speed(6.7%).

Conclusions: EMG equipment influences the kinematic pattern of the golf swing.
Analysis of isokinetic parameters in the development of anterior knee pain syndrome: A prospective study in a military setting
Authors: Van Tiggelen Damien , Witvrouw Erik , Coorevits Pascal , Croisier Jean-Louis , Roget Philippe
Published: October 2018

Objectives: To explore the role of muscular strength and imbalance as predisposing factors in the development of anterior knee pain syndrome(AKPS).

Methods: 96 male military recruits without history of knee pain volunteered for the study. Each volunteer underwent an isokinetic test prior to the start of a strenuous training program (approximately 8 to 12 hours/day for 6 weeks). The isokinetic test consisted of concentric contractions of the knee flexors and extensors at 60°/s and 240°/s. A detailed history and clinical examination of the patellofemoral joint was performed on each recruit. Independent sample t-tests were used to compare the isokinetic muscle parameters in recruits who developed AKPS during the training (pathological group) and in those who did not (control group). Binary logistic regression analysis was used to define the predictive outcome of anthropometrics and the isokinetic parameters for the development of AKPS.

Results: 31 recruits developed AKPS. Absolute and bodyweight normalized peak extensor torque at 60°/s was significantly lower in the pathological group in comparison to the control group. Significant lower peak torque/BMI (Body Mass Index) were also indicated at both velocities. Recruits who developed AKPS had a shorter stature. No regression model could be set up to give any predictive value to the analyzed parameters.

Conclusions: Recruits with shorter stature and lower quadriceps strength are more prone to develop AKPS during BMT. However, as the etiology of AKPS is multifactorial these parameters alone may not suffice to predict the occurrence of this pathology. On the other hand, the results of this study emphasize the importance of the reinforcement of quadriceps strength in the treatment and prevention of AKPS.