bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the mechanical and electromyographic output during isotonic and isometric exercise in men and women
Authors: Schmitz Randy J. , Arnold Brent L. , Perrin David H. , Granata Kevin P. , Gaesser Glenn A. , Gansneder Bruce M.
Published: October 2018

{\it Purpose:} The purpose of this study was to determine if surface electromyography (EMG) could be used to index fatigue during isotonic and maximal voluntary isometric contractions (MVIC) of the knee extensors in men and women.

{\it Methods:} Ten males (age = 22.1 \pm 3.3 yr, ht = 180.3 \pm 5.5 cm, mass 78.7 \pm 5.1 kg) and ten females (age = 23.9 \pm 4.6 yr, ht = 163.7.3 \pm 11.1 cm, mass 63.2 \pm 7.4 kg) underwent one isometric (120 s MVIC of the knee extensors) and one isotonic (120 maximal effort isotonic contractions at a resistance of 25% of the MVIC peak torque determined on the testing day) exercise session separated by at least 48∼hrs. The EMG signal was collected from the vastus lateralis during both exercise protocols using standard EMG collection techniques. Average torque (AT) was calculated from each 3 s window of the 120 s MVIC, and the average peak power (APP) was calculated for every 3 consecutive contractions during the dynamic exercise.

{\it Results:} Both the isometric and isotonic fatigue protocols resulted in significant (p<0.05) decreases in AT and APP, respectively. During the isotonic exercise protocol, decreases in APP during contractions 31--54 were significantly greater (p<0.05) for males than females. Time-amplitude domain processing of the EMG data demonstrated significant decreases in the root mean square amplitude during the course of isometric exercise (p<0.05) but not during isotonic exercise (p>0.05). A main effect for gender (p<0.05) revealed larger EMG amplitude for females when compared to males during isotonic exercise.

{\it Conclusions:} These results indicate that gender may be a factor in the development of dynamic fatigue and that EMG can index fatigue during a sustained MVIC.
Isokinetic strength and strength endurance of the lower limb musculature ten years after achilles tendon repair
Authors: Horstmann T. , Lukas C. , Mayer F. , Winter E. , Ambacher T. , Heitkamp H.-C. , Dickhuth H.-H.
Published: October 2018

Achilles tendon repair with following immobilisation causes atrophy of the calf musculature. The aim of this study was the long term evaluation of the strength and strength endurance deficit ten years after the injury. 63 patients (48 male, 15 female) were tested 10.8 years after achilles tendon rupture repair and subsequent 6-week immobilisation. The test was made in the eccentric (60 $^{\circ}$ /s), isometric and concentric(60 $^{\circ}$ /s, 180 $^{\circ}$ /s) mode for plantarflexion and dorsiflexion with a Lido Active dynamometer. The mean peak torque of the best 3 of 5 movements and the work over 1 minute(180 $^{\circ}$ /s) were evaluated for plantarflexion and dorsiflexion. The circumference of the calf musculature and the range of motion of the ankle (ROM) were measured. Differences to the non-operated side were assessed with the Wilcoxon matched pairs test and adjusted with the Bonferroni method. The mean peak torque in all modes showed no statistically significant difference between the operated and non-operated legs ten years after immobilisation. The work over 1 minute was markedly reduced for the operated leg in plantarflexion (516 J operated versus 634 J non-operated, $p< 0.001$ ). The circumference of the calf musculature( $-1.1$ cm) and the ROM( $-3.5$ $^{\circ}$ plantarflexion, $-1.9$ $^{\circ}$ dorsiflexion) were also reduced ( $p< 0.001$ ). It seems that a selective atrophy of the slow twitch fibers is relevant for the durable loss of musculature and the weakened calf musculature in the strength endurance test. Early remobilization should be chosen after reconstruction of the achilles tendon, and more strength endurance training must be done at the end of the rehabilitation.
Isokinetic evaluation of the ankle plantar and dorsiflexion strength to determine the dominant limb in basketball players
Authors: Theoharopoulos A. , Tsitskaris G.
Published: October 2018

The purpose of this study was to demonstrate limb dominance normative strength values (peak torque, relative peak torque, work and relative work) for the plantar and dorsiflexion muscles in professional basketball players, using the Cybex 1200 isokinetic dynamometer. Paired t-tests showed no significant differences between the two limbs, except for peak torque and relative peak torque during plantar flexion at 60 $^{\circ}$ /s( $p<0.05$ ). The ratio plantar/dorsiflexion was also analyzed, with no significant difference between the two limbs. The results of this research study provide very useful information about the level of strength in this particular area, and are useful for prescribing proper rehabilitation programs for injured basketball players.
Isokinetic assessment in schoolchildren with low back pain
Authors: Negrini Stefano
Published: October 2018

In recent years there has been growing concern regarding back pain in schoolchildren. Our research team studied the risk factors in this particular age group including a careful evaluation, still in progress, of trunk performance. The aim of this paper is to present a review of literature and the pertinent questions relating to this field. The issues that will be discussed are:

1. Prevalence and risk factors of low back pain in teenagers: are they related to trunk muscles?

2. Low back pain and school backpacks: some unexpected results relating to a particular trunk muscle performance risk factor

3. Normative isokinetic trunk performance parameters in schoolchildren

4. Correlation of sporting activities with back pain and isokinetic trunk strength

5. Preliminary results associating isokinetic trunk strength and back pain

6. Pertinent new questions
Scapular plane isokinetic shoulder elevation: Effect of shoulder and motor centres of rotation transient misalignment on moment data
Authors: Mandalidis D.G. , Florides P. , O'Brien M.
Published: October 2018

During isokinetic shoulder elevation in the coronal and sagittal planes, the centre of rotation of the glenohumeral joint was displaced 8-cm vertically relative to the centre of rotation of the dynamometer's actuator arm. It was suggested that in order to account for this displacement, the recorded maximum moment values should be reduced by 12.5%. displacement of the glenohumeral centre of rotation (DGCR) during isokinetic shoulder elevation in the scapular plane and to conduct an error analysis of the dynamometer's moment recordings. The DGCR was assessed in twenty healthy volunteers, during isokinetic concentric elevation of the left shoulder, in the scapular plane, using a two-dimension motion analysis system. Measurements were performed at 30, 60 and 120°·s $^{-1}$ , between 30--90° of shoulder elevation and were analysed every 12°. The glenohumeral centre of rotation was superomedially displaced relative to the centre of rotation of the actuator arm, throughout shoulder elevation (P < 0.001). The effect of isokinetic velocity on the DGCR was not significant. The DGCR resulted also in changes of humeral lever arm orientation and length relative to the pre-set orientation and length of lever arm. As a result of these changes, dynamometer's recordings underestimated corrected angle-based maximum moments by ≤ 6.2%. isokinetic elevation of the shoulder in the scapular plane was probably attributed to normal kinematics of shoulder elevation that requires synchronous function of both the scapulothoracic and glenohumeral joints. The cutaneous markers and the 2-D kinematic analysis system used for the assessment of a 3-D shoulder motion may effect the precision in detecting movements of the shoulder under the skin. The present findings are also limited to the position, stabilisation method and range of motion tested.
Isokinetic and isometric shoulder rotation strength in the protracted position: A reliability study
Authors: Smith Jay , Padgett Denny J. , Kotajarvi Brian R. , Eischen Joseph J.
Published: October 2018

Scapular position has been hypothesized to influence rotator cuff function, but no current methods exist to reliably measure shoulder rotation strength in different scapular positions. The purpose of this study was to develop a reliable technique to measure isokinetic (ISOK) and isometric (ISOM) shoulder rotation strength with the scapula protracted. Ten healthy volunteers(5 male, 5 female, ages 20--41) completed two to three ISOM and five ISOK (90 degrees/second) internal rotation (IR) and external rotation (ER) repetitions in a position of scapular protraction with the shoulder abducted 45 degrees in the scapular plane. Subjects returned 24--72 hours later to repeat testing. All torque measurements in the protracted position exhibited excellent intersession reliability (ICCs > 0.97). Shoulder rotational torque can be measured in the protracted scapula position with excellent reliability using the new technique described. Establishing the reliability of the protracted technique is a necessary prerequisite for the completion of future studies examining quantitative differences in rotational torque generation between the neutral and protracted scapula positions in the functional shoulder position of 45 degrees of scapular plane abduction.
Isokinetic evaluation of the healthy knee: Position of the joint at the peak torque
Authors: Slocker de Arce A. , Sánchez J. Carrascosa , Camacho F.J. Fernandez , Clemente de Arriba C. , Pellico L. Gómez
Published: October 2018

Sixty healthy young volunteers were tested bilaterally in order to determine the angle of peak torque (APT) during flexion and extension of the knee at velocities of 60°/s and 120°/s. No differences in laterality were observed in the APT, except for flexion in females, where this angle was greater on the right side at both velocities. In males, the extensor muscle group reached the peak torque sooner than the flexor group at both velocities. In addition, in extension and for both velocities, men reached the APT earlier than women. Thus muscle and gender have an effect on the APT.
Effect of eccentric hamstring contractions at short and long length on delayed onset muscular soreness (DOMS)
Authors: Brassinne E. , Poortmans J. , Lissassi V. , Duchateaux J.
Published: October 2018

Article without abstract.
Plantarflexion/dorsiflexion strength and isokinetic range of motion following injury to the ankle lateral collateral ligament
Authors: Poulis S. , Soames R.W.
Published: October 2018

Isokinetic range of motion (ISORoM) and peak torque (PT) at the ankle joint were examined in 37 patients, in two different knee positions(extended and flexed at 90°), six months following Lateral Collateral Ligament (LCL) trauma: 2nd and 3rd degree sprains had been sustained by 18 and 19 patients respectively. Patients were immobilized for six weeks in a plaster-of-Paris cast, with 3rd degree sprains undergoing surgical repair prior to immobilization: all patients followed the same physical therapy regime designed to regain full range of motion by mobilizing the joint, strengthen the muscles and improve proprioception. Significant differences(p < 0.01) in ISORoM were observed between the injured and noninjured ankle for each group, with those with 3rd degree sprains also showing a significant reduction (p < 0.01) in ISORoM compared with 2nd degree sprains. No differences were found in PT generation during concentric and eccentric contractions for both muscle groups. Measurement of the ISORoM and muscular strength, following LCL trauma, appears to be a useful tool in clinical evaluation and treatment planning.
Muscle oxygenation, muscle force and electromyographic activity during isometric contraction
Authors: Yamada Eiji , Kusaka Takashi , Miyamoto Kensaku , Tanaka Satoshi , Morita Shin , Tanaka Shouichi , Mori Satoshi , Norimatsu Hiromichi , Itoh Susumu
Published: October 2018

The purpose of this study was to investigate the relationships of muscle oxygenation determined by using near-infrared spectroscopy with muscle force and electromyography during isometric contraction in ten healthy males. The subjects performed sustained isometric extension at 30%, 50% and 70% of the maximal voluntary contraction (MVC) for 10 seconds, respectively. Near-infrared spectroscopy and surface electromyography were simultaneously recorded from the right vastus medialis muscle. The rate of decrease in muscle oxygenation levels at the three intensities were significantly different (p< 0.01). A significant different was also found between the rate of decrease in total hemoglobin and myoglobin at 30% of MVC and that at 70% of MVC (p< 0.01). Integrated electromyography was positively correlated with muscle oxygenation level (r = -0.641, p < 0.0001). These results suggested that muscle oxygenation level during isometric contraction reflects muscle force and muscle activity.
Sex differences in isokinetic strength and power of knee muscles in 10–12 year old swimmers
Authors: Mameletzi D. , Siatras Th.
Published: October 2018

The aim of the study was to determine knee muscles absolute and relative strength and power, as well as flexor/extensor (F/E) ratios, in prepubescent male and female swimmers, during concentric isokinetic testing. Twenty boys and 20 girls, aged 10–12 years, participated in this study. Gravity corrected concentric isokinetic peak torque (strength) and average power (power) were measured by a Cybex Norm dynamometer at the angular velocities of 60, 120 and 180°/s, during unilateral knee extensions and flexions. The relative values of strength and power were expressed per kilogram of lean body mass. Knee extensors strength and power do not differ significantly between boys and girls at the angular velocities of 60 and 120°/s. In contrast, at the higher angular velocity of 180°/s boys exerted greater values than girls (p < 0.01). With respect to the knee flexors, boys exerted greater values than girls only at the angular velocities of 120 and 180°/s (p < 0.01). When relative strength and relative power were calculated, no significant differences existed between boys and girls for both muscle groups. Moreover, the shapes of strength-velocity and power-velocity curves, as well as knee F/E ratios, were similar for both groups.
The relationship between ACL deficiency, functional performance and a break in the isokinetic moment curve of the knee flexors
Authors: Herrington Lee , Turner Melissa , Horsley Ian
Published: October 2018

Changes in the isokinetic moment curve of the knee flexors have been proposed to be associated with functional instability in anterior cruciate ligament deficient (ACLD) patients. The purpose of this study was to assess if this relationship exists between breaks in the knee flexor moment curve and functional instability in an ACLD patient population.

The study involved two groups: an asymptomatic control group(n=20) and a second experimental group(n=20) diagnosed as having an anterior cruciate ligament rupture. Both groups underwent isokinetic strength assessment of the knee flexors, with the moment curves being inspected for irregularities or breaks. All subjects also completed Lysholm and Tegner questionnaires and had a standardized assessment using the International Knee Documentation Committee(IKDC) form. The findings of the questionnaires were then correlated with presence of breaks in the torque curve to assess association between these factors.

Breaks in the knee flexor moment curve were established to occur in some patients with ACL deficiency; these patients also had lower scores on a variety of functional indices. Further investigation would appear to be warranted on a larger population to establish if the presence of break phenomena in knee flexor torque curves can be used to identify those patients who can and cannot cope with ACL deficiency.
Influence of baseball practice on strength ratios in shoulder rotator muscles: A new position for isokinetic assessment
Authors: Dupuis C. , Tourny-Chollet C. , Delarue Y. , Beuret-Blanquart F.
Published: October 2018

Objective: To determine the strength ratios in the shoulder rotator muscles of teenage baseball players, using a new test position.

Methods: Ten asymptomatic baseball players of the French cadet team(15.87 ± 0.80 yr) underwent dynamic isokinetic strength assessment of the shoulder rotators at two angular velocities: 90 and 180°.s ^{-1} . The peak torque of the internal rotators(IR) and external rotators (ER) was recorded. One conventional ratio and two dynamic ratios were determined at each angular velocity. The mean group values were statistically analyzed.

Results: Mean ER peak torque was significantly higher in the dominant than in the non-dominant arm at both velocities (p < 0.05). The dynamic ratio (ER conc/IR ecc) was significantly higher in the dominant than in the non-dominant arm (p < 0.01). In the same position, baseball players had higher conventional and dynamic ratios (IR conc/ER ecc) than those reported in the literature for sedentary subjects.

Conclusion: Intensive baseball practice affects the shoulder rotator muscles. The IR values indicated greater strength than in sedentary subjects. The difference in ER between the dominant and non-dominant arms underlines the effect of pitching technique and suggests the need for further investigations.
Isokinetic assessment of muscle strength following anterior cruciate ligament reconstruction
Authors: Cardone C. , Menegassi Z. , Emygdio R.
Published: October 2018

The purpose of this prospective study was to monitor the development of muscular strength and find possible deficits in following reconstruction of the anterior cruciate ligament and rehabilitated by means of the accelerated protocol. Isokinetic assessments of 67 patients were conducted at 2, 4 and 6 months postoperatively. A significant increase (30%) in knee extension strength was found in the operated knee between 2 and 6 months leaving a deficit of 25% relative to the healthy knee without clinical evidence of instability. Knee flexion strength did not vary during the treatment. We conclude that knee extension strength constitutes a reasonable developmental parameter during accelerated ACL reconstruction rehabilitation.
Isokinetic strength and fatigue of the elbow flexors and extensors in sedentary women
Authors: Maquet D. , Forthomme B. , Demoulin C. , Jidovtseff B. , Crielaard J.M. , Croisier J.L.
Published: October 2018

Objective. To establish the inter-session reproducibility of isokinetic concentric strength and fatigue profile of the elbow flexors and extensors in sedentary women.

Methods. Forty healthy women who were physically inactive or engaged in recreational sports were included in the study. Strength was evaluated at 60 and 180°/s. The fatigue protocol consisted of 30 maximal-intensity elbow flexion and extension at 180°/s.

Results. The extensors were stronger than flexors while no dominance effect was apparent. In addition the work output of the extensors during the fatigue protocol was larger than the flexors', the previous being more fatigue resistant. A dominance effect was observed for the extensors in the fatiguing protocol. Reproducibility expressed by the coefficient of variation was less or equal to 11%.

Conclusions. This study highlights satisfactory reproducibility of isokinetic strength and fatigue parameters. The values derived may be useful for interpretation of clinical tests or characterization of pathological states in women with similar characteristics.
Reproducibility of postural stability scores in blind athletes
Authors: Aydo� Sedat Tolga , Aydo� Ece , Çakci Aytül , Doral Mahmut Nedim
Published: October 2018

Objective: To evaluate the reproducibility of postural stability scores in blind athletes.

Design: Within-subject, repeated trials of postural stability.

Setting: Laboratory located at a physical medicine and rehabilitation center.

Participants: Eighteen congenitally blind goal-ball players.

Main outcome measures: Three postural stability indices: overall, anteroposterior and mediolateral was evaluated. Means of each day and of the best score of each day were calculated from the three test trials.

Results: No significant differences were determined between the mean score on each of the two days or between the mean score and the mean of the best score of each day. Intraclass coefficients (ICC) for the two testing days ranged from 0.59 to 0.83 based on the mean value, and from 0.40 to 0.86 based on the best value. The standard error of measurement (SEM) ranged between 0.4–1.1, which was equivalent to 18% of the stability index scores.

Conclusions: Based on both ICC and SEM results, findings derived from this postural balance test have acceptable reproducibility in the overall and anteroposterior indices but only fair reproducibility in the mediolateral index.
An investigation of hand dominance, average versus maximum grip strength, body mass index and ages as determinants for hand evaluation
Authors: Ertem Kadir , Harma Ahmet , Cetin Aymelek , Elmali Nurzat , Yologlu Saim , Bostan Haci , Sakarya Bulent
Published: October 2018

Measurement of grip strength is an important component in hand evaluation. It assesses the patient's initial limitations and provides a quick reassessment of patient's progress throughout the treatment. This investigation was conducted to examine the determinants of hand dominance of average versus maximum grip strength, body mass index (BMI) and age for hand evaluation. Subjects were 877 apparently healthy male adult volunteers from the Inonu University – students and personnel; average age 21.14±2.09(19–40 years). A good correlation was found between the BMI hand strength measures. Grip strength was measured instrumentally. The rule "dominant hand(DH) is approximately 10% stronger than the non-dominant hand (NDH)" was found to be valid for left handed persons only (7%) otherwise these measures should be considered equivalent in both hands. The difference between maximum and average of three consecutive measurement of grip strength was found significant for both hands. As the significant difference was found between RGSmax (Maximum Grip Strength of Right Hand) and RGSav (Average Grip Strength of Right Hand); LGSmax (Maximum Grip Strength of Left Hand)/LGSav (Average Grip Strength of Left Hand) measures for RDH. RGSmax and LGSmax where correlated only for LDH. Therefore, average of three consecutive measurement of grip strength is more consistent for standard hand evaluation.
Differences in recovery process between adult and prepubertal males after a maximal isokinetic fatigue task
Authors: Kotzamanidou M. , Michailidis I. , Hatzikotoulas K. , Hasani A. , Bassa E. , Kotzamanidis C.
Published: October 2018

The purpose of this study was to investigate the differences in recovery between adult and prepubertal males after a maximal isokinetic fatigue protocol. Ten adults and 14 prebupertal boys exerted 25 subsequent maximal isokinetic knee extensions at 60°/s. The electromyogram (EMG) of the vastus lateralis (VL), vastus medialis (VM) and biceps femoris (BF) was recorded. The obtained results showed that the Peak Torque (PT) decreased at a higher rate in adults compared to children. The recovery of PT, and the agonist muscle activity was faster in children in comparison to the men. No differences were observed in the recovery of the antagonist muscle between age groups. The findings indicated that the PT recovery is faster in children and this could be partially attributed to neural factors since in children the recovery of their agonist muscle activation was faster than adults.
Consolidated reference values for grip strength of adults 20 to 49 years: A descriptive meta-analysis
Authors: Bohannon Richard W. , Peolsson Anneli , Massy-Westropp Nicola
Published: October 2018

Building on a previous meta-analysis, this study focused on the utility of consolidating grip strength data from apparently healthy subjects 20–49 years of age. All data were obtained using a Jamar dynamometer and procedures generally consistent with the recommendations of the American Society of Hand Therapists. The meta-analysis revealed that the seven sources provided homogeneous data (Q=0.21–0.81, p>0.667) for the left and right sides of men and women subjects. Means and confidence intervals are provided that can be used to interpret the normality of grip strength obtained from men and women 20–49 years of age. By consolidating the data from multiple studies conducted in five countries, a better overall estimate of normal is obtained. Providing reference values for three decades combined simplifies normative comparisons.
Isokinetic torque and surface electromyography during fatiguing muscle contractions in young and older men and women
Authors: Lindström Britta , Karlsson J. Stefan , Lexell Jan
Published: October 2018

The overall aim was to investigate the fatigue pattern and perceived fatigue during repetitive dynamic contractions in young and older men and women. Sixteen older men and women (mean age 73 ± 3 years) and 22 young men and women (mean age 28 ± 6 years) performed 100 repeated maximum concentric isokinetic knee extension contractions at 90°·s $^{-1}$ (1.57 rad·s $^{-1}$ ). Throughout the 100 contractions, peak torque (PT) and surface electromyography (EMG) signals from the rectus femoris muscle and the vastus lateralis muscle were recorded simultaneously, together with perceived fatigue (CR-10 scale of Borg). The mean frequency of the power spectrum (MNF) and the root mean square of the signal amplitude (RMS) of the EMG were affected by age and with a sex related difference but for PT the difference of the fatigue pattern was most evident between the sexes. In addition, the young men rated the highest fatigue. Based on EMG, PT and ratings of perceived fatigue it was concluded that the old men fatigued most, the old women fatigued least and the young men perceived greatest fatigue.
The influence of different ranges of motion testing on the isokinetic strength of the quadriceps and hamstrings
Authors: Dervišević Edvin , Hadžić Vedran , Karpljuk Damir , Radjo Izet
Published: October 2018

Objective: To evaluate bilateral quadriceps and hamstrings strength, at two different ranges of motion (RoM): 30° (SRoM) and 90° (FRoM), using different angular velocities.

Background: Recent studies have indicated that short RoM isokinetic testing of knee muscles yielded strength findings that were compatible with those derived from a much larger RoM. However, findings were based on a single adjusted velocity in each of the RoMs.

Method: Sixteen healthy male students volunteered to participate in this study. Two testing sessions, a week apart, were performed. In the first session testing started with a RoM of 90° (FRoM, 0° – full extension) and angular velocities of 60 and 180°/s. Measurements related to concentric (quadriceps and hamstring) and eccentric(quadriceps only) contractions. In the second part of the test, the RoM was adjusted to 30° (SRoM, 30–60° knee flexion) with velocities of 30 and 60°/s, respectively. The order of RoM testing was reversed in the second session. All tests were conducted bilaterally.

Results: Both FRoM- and SRoM-based scores have shown good reproducibility based on the Bland Altman plots and low values of standard error of measurement and coefficient of variance of standard deviation. No statistically significant differences were noted between the FRoM and SRoM-based strength scores. The results suggest that range of motion used in isokinetic testing alone or in combination with other factors, namely side tested and isokinetic velocity, does not significantly influences changes in peak torque values for both quadriceps and hamstrings.

Conclusion: This study suggests that SRoM isokinetic testing provides an effective alternative to the commonly applied range.
Isokinetic muscle strength and functional restoration following surgical repair of the rotator cuff: A prospective study
Authors: Cools Ann , Declercq Geert , Sneyers Claire , Witvrouw Erik
Published: October 2018

The objective of this prospective study was to evaluate isokinetic muscle strength and functional outcome following surgical rotator cuff repair in patients with full-thickness tears compared to preoperative results and compared to normal values. Twenty-four patients and 29 healthy subjects participated in the study. We measured isokinetic lateral and medial rotation strength in the patient group prior to surgery, and 18 months postoperatively on both sides and performed the same evaluation procedure in the control group in a single assessment. Constant-Murley scores were taken for assessment of the patient's functional abilities. Pre-operative strength averaged 55.4%, 68.6%, 66% and 79.7% for lateral and medial rotation at 60°/sec, and lateral and medial rotation at 180°/sec respectively, compared to the control group. Eighteen months postoperative strength increased significantly compared to the non-injured side (p<0.05) for the measurements at 60°/sec and nearly reached normal strength values since no group differences were apparent in the postoperative session. Measurements at 180°/sec did not show significant improvement. Constant-Murley scores increased significantly from 40.4 preoperatively, to 68 postoperatively. However, these scores did not attain the normal values from the control group. It was concluded that although significant strength gains are present 18 months after rotator cuff repair, shoulder function is not completely normalised. Clinicians should pay attention to full functional restoration in the rehabilitation program.
Isotonic muscle function is selectively reduced after muscle damage induced by isometric exercise at a long muscle length
Authors: Philippou A. , Bogdanis G.C. , Maridaki M.
Published: October 2018

This study investigated the hypothesis that isotonic muscle performance following mild muscle damage would be disproportionately affected when measured at different parts of the range of motion. Seven male volunteers performed 50 maximal isometric contractions with the elbow flexors at a lengthened position. Maximal isotonic performance was measured before and for four days post-exercise at two parts of the range of motion of elbow flexion, including mainly the descending (L) or the ascending limb (S) of the angle–force curve. On day 1 post-exercise, muscle damage was evidenced by a decrease in peak isometric force (−20.3 ± 2.7%, p<0.01), a shift in optimum angle for force generation towards a greater elbow angle (by 0.12 ± 0.03 rad, p<0.05), and an increase in serum creatine kinase activity and muscle soreness (P<0.01). Isotonic performance indices were decreased only in the S condition (p<0.01). Shift in optimum angle and isotonic performance indices recovered on day 2. The disproportionate decrease in isotonic performance in the S condition may be explained by the shift of the optimum angle towards a longer muscle length, which would benefit force generation at elbow angles beyond the optimum angle but impair force at the more acute elbow angles.
Muscular activity in treadmill and overground running
Authors: Baur Heiner , Hirschmüller Anja , Müller Steffen , Gollhofer Albert , Mayer Frank
Published: October 2018

It still remains unclear whether muscular activity on the treadmill(T) differs compared to overground (O) running. The purpose of this study was therefore to examine possible differences in muscular activation between T and O. 14 healthy runners were analyzed in a neutral running shoe at 12 km·h $^{-1}$ on a treadmill and in a field test. Muscular activity (EMG) of the tibialis anterior, peroneus longus, and soleus were measured. Time and amplitude quantities were assessed during the gait cycle. The EMG of the peroneus longus exhibited a later onset, a later maximum and shorter total time of activation (p<0.05) in O. The soleus showed a higher amplitudes in O during the push-off phase(p<0.05). Altered peroneus longus activity may indicate its role as an ankle stabilizer and demonstrates a compensatory response due to changing mechanical conditions. Weaker amplitudes of the soleus in the push-off during T suggest adaptation to the movement of the treadmill belt, and/or changes in load receptor input. Differences in muscle activity between T and O running must thus be taken into consideration in studies of neuromuscular control of movement.
Muscle performance enhancement in some non-orthopedic conditions: Evidence based on modified randomized controlled trials
Authors: Dvir Zeevi
Published: October 2018

Article withoout abstract.
Correlation of forearm strength and sport climbing performance
Authors: Schweizer A. , Furrer M.
Published: October 2018

The aim of the study was to determine whether forearm muscle strength correlates with sport climbing performance. Three different movements of the forearm musculature in 25 recreational climbers (performance on sight(os) style mean F7a+, range 6b+ – 7c; red point (rp) style 7b+, range 7a – 8b+) were examined. A special isokinetic device was built to investigate eccentric and concentric isokinetic maximum strength of wrist (wr) flexion, proximal interphalangeal joint (pi) flexion of the middle- and ringfinger and a "rolling in a bar" movement involving both interphalangeal joints and the metacarpophalangeal joint (ro) of all fingers. There was no correlation between absolute maximum strength and climbing performance. Relative strength (strength/body weight) of all three exercises however correlated significantly with climbing difficulty of rp and os style, except pi flexion and os style. Correlation coefficient was highest between rp and concentric wr flexion. Among forearm musculature concentric wrist flexion was the best predictor for sport climbing performance.
The contribution of isokinetic strength parameters to the performance of cricket batsmen
Authors: Nunes Terence , Coetzee Ben
Published: October 2018

The purposes of this study were to determine which of the isokinetic knee and shoulder strength parameters discriminate between successful and less successful provincial academy cricket batsmen and to assess the contribution of isokinetic knee and shoulder strength parameters to the performance of these athletes. Twenty-two contracted batsmen (20.63 ± 1.62 years) from the Gauteng and North-West Cricket Academies in South Africa were tested during the 2004 and 2005 seasons. The discriminant analyses showed that no strength, work or power parameters discriminated significantly between the successful (top 5 ranked batsmen of both seasons) and less successful academy batsmen. A forward stepwise multiple regression analyses showed that the contribution of individual knee-related isokinetic parameters ranged 4–16% whereas for the shoulder the range was 4–28%. However knee parameters accounted for a total of 57% of the difference between the more and less successful batsmen while the corresponding share in terms of shoulder parameters was even higher: 61%. The conclusion that can, therefore, be drawn is that isokinetic knee and shoulder strength parameters contribute to the performance of provincial academy cricket batsmen and that these components should be included in the talent identification protocols for young promising batsmen.
Does neuromuscular electrical stimulation influence muscle recovery after maximal isokinetic exercise?
Authors: Vanderthommen M. , Soltani K. , Maquet D. , Crielaard J.M. , Croisier J.L.
Published: October 2018

Neuromuscular electrical stimulation (ES) and passive recovery (PR) were compared in ten healthy men after a provocation exercise inducing delayed onset of muscle soreness (DOMS). The exercise consisted of 3 sets of 30 maximal eccentric contractions performed by the knee flexor muscles of the dominant leg on an isokinetic dynamometer at 60°/s angular velocity. There was an interval of 8 weeks between both bouts and the order of the recovery mode (ES or PR) was block-randomly assigned. ES recovery consisted of a 25-min continuous and non-tetanic (5 Hz) stimulation of the hamstring muscles. Concentric and eccentric hamstrings peak torques were evaluated before and immediately after the provocation exercise, after the recovery period, as well as 24 h (d1), 48 h (d2), 72 h (d3) and 168 h (d7) after the bout. Subjective perception of muscle soreness (VAS, 0–10 a.u.) was evaluated before exercise and at d1, d2, d3 and d7. To assess the CK activity, five blood samples were drawn before exercise and at d1, d2, d3 and d7. For both recovery modes, the greatest reductions in isokinetic muscle performances were measured on d2 (66.3 ± 24.1% of initial values (ES) vs. 57.4 ± 26.5% (PR) for the concentric mode and 55.6 ± 16% (ES) vs. 53.1 ± 19.3% (PR) for the eccentric mode). d2 also corresponded to the highest painful sensations(5.4 ± 2.14 a.u. (ES) vs. 6.15 ± 2.55 a.u. (PR)). Peak activities of CK were reached on d3 (47507 ± 19973 IU/l (ES) vs. 75887 ± 41962 IU/l (PR)). Serum CK was lower with ES than PR at d3 (p⩽0.05) but all other parameters changed in a manner that was not statistically different between the two recovery protocols (p>0.05). This strong trend could be explained by an electro-induced hyperperfusion that may efficiently wash out the muscle from the cellular debris resulting from the initial injury, and hence diminish the inflammatory response and the delayed amplification of tissue damages.
Influence of an isometric fatiguing exercise on the length and passive-elastic properties of the calf muscle-tendon unit of minimally active young women
Authors: Finlayson Michele H.M. , Majerus Amber L. , Temes Amy L. , Wright Allison M. , Gajdosik Richard L.
Published: October 2018

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.
Effects of knee angle on lower extremity extension force and activation time characteristics of selected thigh muscles
Authors: Papadopoulos Christos , Kalapotharakos Vasilios I. , Chimonidis Evripidis , Gantiraga Evaggelia , Grezios Apostolos , Gissis Ioannis
Published: October 2018

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.
Reproducibility of isokinetic test findings for assessment of wrist spasticity in stroke patients
Authors: Çetin Nuri , Dilek Ayse , Aytar Aydan , Akman Mahmut Nafiz
Published: October 2018

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.
The effects of muscle fatigue and proprioceptive deficits on the passive joint senses of ankle inversion and eversion
Authors: Lin Yang Hua , Li Chen Wei , Tsai Li Ying , Liing Rong-Jiuan
Published: October 2018

Objective: To investigate whether muscle fatigue of ankle invertors and evertors reduces the ability to detect inversion and eversion angles in subjects with an ankle proprioceptive deficit.

Design: A cross-sectional before-after study with repeated measures design.

Setting: Research laboratory.

Subjects: Thirty young adults with defective passive joint sense of ankle inversion were recruited into this study and compared with 30 similar controls without ankle proprioceptive deficits.

Interventions: Muscle fatigue of ankle invertors and evertors was defined as occuring when the maximal isokinetic torque declined to below 50% of the peak torque.

Main measures: The absolute differences between the angles detected and assigned, with target angles at inversion 10°, inversion 20°, and eversion 10° trialled in random orders.

Results: Proprioceptive deficits and muscle fatigue of ankle inversion and eversion had a significant interaction with the ability to detect small amplitude target angles. Detecting 10° of ankle eversion and inversion showed significantly greater errors than for 20° of ankle inversion. Following muscle fatigue or in subjects with proprioceptive deficits there were greater errors in detecting small amplitudes of ankle positions (10° of ankle inversion and eversion).

Conclusions: The potential deleterious effects of fatigue and proprioceptive deficits on the ability to detect the small range of lateral movements of ankle joint was addressed in this investigation.. Fatigue worsens chronic proprioceptive ankle deficits and hence may enhance the risk of injury.
The effect of resistance training on handgrip strength in young adults
Authors: Thomas Elin Magnusson , Sahlberg Margareta , Svantesson Ulla
Published: October 2018

Handgrip strength is used to evaluate hand function. Handgrip strength may be used to assess generalized upper extremity strength and activities of daily living. This study aimed to evaluate the effect of general resistance training of the upper extremities on handgrip strength and to present hand-grip strength values, measured with the Grippit®, for young adult subjects in Sweden. Forty one healthy subjects, 27 women and 14 men, volunteered to participate in the study. The women's group were randomly split between a training group (TG; n=15) and a control group (CG; n=12). Training consisted of general resistance for the upper extremities three times a week for 8 weeks. Values outcome measures included maximal voluntary contraction (MVC) and sustained MVC (SMVC). A significant difference (p<0.001) in strength was found between the right and the left hand (8–11% when accounting for right hand dominance. The TG showed significantly higher (p<0.05) MVC for the right hand after training. It appears that handgrip strength may be increased by eight weeks of general resistance training for the upper extremities. The findings in this study support the 10% rule for a population that is right-handed.
Patellar tendon graft vs. Semitendinosus and Gracilis graft for posterior cruciate ligament reconstruction: An isokinetic and functional study one year after the operation
Authors: Tornese Davide , Bandi Marco , Volpi Piero , Schonhuber Herbert , Denti Matteo , Ricci Gabriele , Melegati Gianluca
Published: October 2018

Objective: to compare the outcomes of arthroscopic reconstruction of the posterior cruciate ligament (PCL) by means of the double bundle technique with the ipsilateral semitendinosus and gracilis (St-Gr) and the single bundle technique with the ipsilateral patellar tendon (PT).

Methods and measures: 14 patients had randomly been assigned to either PT ot St-Gr graft for PCL reconstruction. The IKDC Knee Ligament Evaluation Form, the Lysholm Knee Scoring Scale, the Cincinnati Knee Rating Scale and concentric isokinetic knee extensor-flexor test at 60 and 180°/s were used to compare the results.

Results: there were no significant differences in the clinical scores. The isokinetic tests, however, disclosed a significant loss of strength at the harvest site.

Conclusion: since biomechanical considerations underscore the importance of recovery of the quadriceps after PCL reconstruction, employment of the semitendinous and gracilis with a possible loss of flexor strength could be rationally more acceptable solution than reconstruction with the patellar tendon and weakening of the extensors.