bluuebunny/crossref_metadata_2025 huggingface dataset:
Targeted Photothermal Therapy of Melanoma in C57BL/6 Mice using Fe3O4@Au Core-shell Nanoparticles and Near-infrared Laser
Authors: Pandesh S , Haghjooy Javanmard Sh , Shakeri-Zadeh A , Shokrani P
Published: October 2018

Background: Gold nanoshells can be tuned to absorb a particular wavelength of light. As a result, these tunable nanoparticles (NPs) can efficiently absorb light and convert it to heat. This phenomenon can be used for cancer treatment known as photothermal therapy. In this study, we synthesized Fe3O4@Au core-shell NPs, magnetically targeted them towards tumor, and used them for photothermal therapy of cancer.Objective: The main purpose of this research was to synthesize Fe3O4@Au core-shell NPs, magnetically target them towards tumor, and use them for photothermal therapy of cancer.Material and Methods: Twenty mice received 2 × 106 B16-F10 melanoma cells subcutaneously. After tumors volume reached 100 mm3,the mice were divided into five groups including a control group, NPs group, laser irradiation group, NPs + laser group and NPs + magnet + laser group. NPs were injected intravenously. After 6 hours, the tumor region was irradiated by laser (808 nm, 2.5 W/cm2, 6 minutes). The tumor volumes were measured every other day.Results: The eﬀective diameter of Fe3O4@Au NPs was approximately 37.8 nm. The average tumor volume in control group, NPs group, laser irradiation group, NPs + laser irradiation group and NPs + magnet + laser irradiation group increased to 47.3, 45.3, 32.8, 19.9 and 7.7 times, respectively in 2 weeks. No obvious change in the average body weight for different groups occurred.Conclusion: Results demonstrated that magnetically targeted nano-photothermal therapy of cancer described in this paper holds great promise for the selective destruction of tumors.
SHRINKING DEFORMATION OF BUILDING MATERIALS AND METHODS OF ITS REDUCTION
Authors: Kozlova V. K. , Bozhok E. V. , Logvinenko V. V. , Sarkisov Yu. S. , Il'evskii Yu. A.
Published: October 2018

Construction materials manufactured with composite cement binders are characterized by shrinking deformation in the course of their hardening. The total deformation consists of three shrinkage types: contractional, humid and carbonizing. The analysis of crack propagation in building materials is important because its changes result in the reduction in the service life of building structures. Humid and carbonizing shrinkages are determined for various construction materials. It is found that contractional shrinkage of construction materials may significantly ex-ceed shrinking deformations which occur during material drying. Possible ways to decrease con-tractional shrinkage are considered. It is shown that one of the more effective ways to reduce shrinking deformations is forced carbonization of building mixes, especially at early stages of hardening.
DESIGN AND PARAMETERS OF WATER-PURIFYING RADIAL FILTERS
Authors: Dzyubo V. V. , Alferova L. I.
Published: October 2018

In radial water treatment filters technologies of filtering in the mode of the decreasing or increasing speeds of the movement of the cleared stream in the filtering material depending on the direction of filtering are realized. Constructive registration of radial filters allows to realize various options of the direction of filtering, decrease or increase in speed of filtering that allows to use as much as possible contaminant capacity of the filtering loading of water treatment filters. The main equations for calculation of technological and design data of the water treatment filters intended for preparation of underground waters, and also a technique of engineering calculation of radial filters with the decreasing filtering speed are given.
Correlation of static and dynamic trunk muscle endurance and bat swing velocity in high school aged baseball players
Authors: Lin Kun-Han , Huang Yi-Ming , Tang Wen-Tzu , Chang Ya-Ju , Liu Ya-Chen , Liu Chiang
Published: October 2018

BACKGROUND: Trunk muscle endurance training is used by most high school baseball or softball coaches. However, evidence demonstrating a relationship between trunk muscle endurance and batting performance is lacking.

OBJECTIVE: This study aimed to establish a relationship between trunk muscle endurance and bat swing velocity in a high school baseball team.

METHOD: Sixty-one high school (15–18 years old) baseball players, taken from the same team, with 6.5 ± 1.3 years of training experience, participated in the following tests: static trunk flexion/extension endurance tests, dynamic trunk flexion/extension endurance tests and a maximum bat swing velocity test.

RESULTS: Bat swing velocity showed significant low-to-moderate negative correlations with static trunk flexor endurance (P=0.001, r=−0.404), dynamic trunk flexor endurance (P=0.016, r= −0.308) and the ratio of static flexor/extensor endurance (P=0.021, r=−0.298).

CONCLUSIONS: These findings support the concept that better trunk flexor endurance might not benefit batting performance. Trunk flexor endurance training should not be over-emphasized when the targeted training goal is to enhance bat swing velocity.
The effects of isokinetic knee extensor and flexor strength on dynamic stability as measured by functional reaching
Authors: Lockie Robert G. , Schultz Adrian B. , Callaghan Samuel J. , Jeffriess Matthew D.
Published: October 2018

BACKGROUND: Team sport athletes require dynamic stability in unilateral activities for their sports, which necessitates some degree of knee flexion and extension strength.

OBJECTIVE: To analyze the possible association of knee extension and flexion strength with dynamic stability, as measured by the Star Excursion Balance Test (SEBT).

METHODS: Sixteen male team sport athletes completed the SEBT, which involves a series of unilateral squats with the subject maximally reaching with the other leg in eight directions. Knee muscle strength was measured isokinetically both concentrically (60°/s, 180°/s, 240°/s) and eccentrically(30°/s). Subjects were divided into better and lesser groups based on mean functional reach distance. A 1-way analysis of variance (p⩽ 0.05) determined between-group differences in reach distances and relative torque.

RESULTS: Subjects with better dynamic stability generated greater knee extensor torque concentrically at 180°/s for the right leg, and at all speeds for the left leg. The effects of knee strength were particularly noteworthy for the left leg, as subjects with better dynamic stability reached significantly further across all 8 directions.

CONCLUSION: The results indicate that greater knee extensor strength may enhance unilateral dynamic stability in team sport athletes.
Test-retest relative and absolute reliability of knee extensor strength measures and minimal detectable change
Authors: Ferri-Morales Asunción , Alegre Luis M. , Basco Angel , Aguado Xavier
Published: October 2018

BACKGROUND: Few studies have assessed the test-retest reliability of the isokinetic strength at 90°/s and the isometric parameters for knee extensors.

OBJECTIVES: To assess the reliability of isokinetic and isometric parameters of knee extensors, and to determine the smallest real difference between the test-retest measures.

METHODS: Knee extensor strength was measured twice, 4 to 5 days apart, using a Biodex dynamometer in forty subjects (12 men, 28 women). The protocols consisted of 5 concentric contractions at 90°/s and 5 isometric contractions.

RESULTS: For women, test-retest reliability was very high for isometric and isokinetic peak-torque (ICC $_{c,1}$ > 0.9), moderate for work (ICC $_{c,1}$ =0.82) and questionable for angle of peak torque (Angle-PT), mean Angle-PT and rate of torque development(RTD $_{0-100 ms}$ (ICC < 0.67). The measurement errors were small for all variables, the SEM% ranged between 3.1% to 7.4%, and SRD% from 8.6% to 19.9%, except for RTD $_{0-100 ms}$ that was the most variable (SEM%=16.4%; SRD=47.5%). No differences were found in Angle-PT and RTD $_{0-100 ms}$ with regard to sex.

CONCLUSIONS: The isokinetic values obtained at 90°/s and isometric peak-torque for knee extensors are highly repeatable with a standardized test protocol and the SRD values can be used to detect real changes. Alternative strategies of analysis should be developed to improve reliability of Angle-PT and RTD $_{0-100 ms}$ . Angle-PT and RTD $_{0-100 ms}$ do not appear affected by gender.
Lactate, cortisol and testosterone values from high-speed resistive exercise workouts done by women
Authors: Caruso J.F. , Urquhart M.A. , Barbosa A.G. , Giebel R.M. , Learmonth L.A. , Potter W.T.
Published: October 2018

BACKGROUND: Few studies examined lactate, testosterone and cortisol changes from supramaximal exercise done by women.

OBJECTIVE: Assess the impact of repetition type and exercise history/background on lactate, cortisol and testosterone changes from high-speed workouts done by women.

METHODS: College-age women (11 competitive athletes, 18 novice athletes) performed two high-speed workouts on an Impulse resistive exercise machine. Each workout entailed two 60-second sets of either tonic or phasic repetitions. There were two hormonal (pre- and post-exercise) measurements per workout. Lactate was measured six times (pre-, and at zero-, five-, ten, 15- and 20-minutes post-exercise).

RESULTS: Mean force showed a main effect for workout (tonic > phasic). Lactate had a time main effect, as zero-, five- and ten-minutes post-exercise results were significantly higher than 15- and 20-minutes post-exercise values as well as pre-exercise data. Cortisol had a group main effect (competitive > novice). Testosterone results included a time effect trend (p=0.12) for higher post-exercise values.

CONCLUSIONS: Results warrant continued inquiry regarding 1): pre- and post-workout salivary hormonal assays, and 2): acute testosterone changes from high-speed supramaximal exercise done by female athletes.
Is it possible to establish reference values for ankle muscle isokinetic strength? A meta-analytical study
Authors: Fish Michael , Milligan James , Killey Jenny
Published: October 2018

BACKGROUND: The importance of measuring ankle muscle strength (AMS) has been demonstrated in a variety of clinical areas. Much data has been accumulated using the Cybex Norm isokinetic dynamometer but a uniform framework does not exist.

OBJECTIVE: To identify pertinent studies which have used the Cybex Norm to measure AMS in order to establish reference values.

METHODS: A narrative review of the literature was used to identify papers that have used the Cybex Norm to measure isokinetic concentric and eccentric AMS.

RESULTS: Fifty five research papers were identified but each study used a different isokinetic protocol.

CONCLUSIONS: It is not possible to produce AMS reference values due to the wide variation in data collection methods. This is therefore an area of research that needs further exploration.
Hip extension strength: Description and validity of a new procedure applied to older women
Authors: Bohannon Richard W. , Šteffl Michal , Musálek Martin , Miroslav Petr , Houdová Veronika , Holmerová Iva
Published: October 2018

OBJECTIVE: We sought to: 1) describe a new procedure for measuring hip extension strength and 2) examine the convergent and known-groups validity of measurements obtained using the procedure.

METHOD: Forty women (72–98 years) volunteered for this cross-sectional, observational study of muscle strength and mobility. Hip extension strength as well as hip flexion and knee extension and flexion strengths were measured using a hand-held dynamometer (HHD). Hip extension strength was measured while participants were supine and the HHD was positioned under their slightly elevated distal leg. Participants were dichotomized as independent or dependent in sit-to-stand and walking.

RESULTS: Hip extension strength was measured without difficulty or untoward effects. Relative to other ipsilateral measures of hip and knee strength, hip extension strength was found to correlate significantly (r=0.345–0.584), to be internally consistent (alpha=0.785 and 0.751), and to load strongly (0.733 and 0.705) on a common construct-lower limb strength. Hip extension strength (left+right/body weight) discriminated (albeit weakly) between known groups, that is, participants who were dependent versus independent in sit-to-stand and walking.

CONCLUSION: Based on these findings we recommend this procedure for measuring hip extension strength in older adults.
What is the actual relative intensity of a resistance training program for men and women?
Authors: Ribeiro Alex S. , Avelar Ademar , Nascimento Matheus A. , Mayhew Jerry L. , Filho Marçal G.A. Campos , Eches Erick H.P. , Ritti Dias Raphael M. , Altimari Leandro R. , Cyrino Edilson S.
Published: October 2018

BACKGROUND: Differences related to sexual characteristics are directly linked to the mechanisms responsible for adaptations from resistance training (RT). Due to these differences, men and women may perform their RT programs at different percentages of maximum strength even when executing the same number of repetitions.

OBJECTIVE: To compare the relative repetition maximum (%1RM) at which men and women perform RT in a program controlling repetitions/set.

METHODS: Thirty men (22.7 ± 4.4 years, 68.4 ± 9.0 kg, 174.5 ± 6.6 cm), and 34 women (22.7 ± 4.1 years, 58.8 ± 11.9 kg, 162.6 ± 6.2 cm) performed 16 weeks of RT, 3 times per week using 3 sets of 8–12 RM. Anthropometric measurements and 1RM test in bench press (BP), and arm curl (AC) were obtained at baseline and after the RT program.

RESULTS: Women performed the training in BP at a higher %1RM than men ($P<$ 0.05) at the beginning (men=59.8 ± 5.1% and women=63.2 ± 7.2%) and at the end (men=66.2 ± 6.5% and women=68.6 ± 7.2%) of the program. Both men and women significantly increased (P< 0.05) the %1RM at which they performed BP exercise (men=+10.7% and women=+8.5%) while maintaining the 8–12 repetition configuration with no significant time x group interaction(P> 0.05). There was not significant main effect for AC (P> 0.05) indicating no change in %1RM at which each sex exercised.

CONCLUSION: We conclude that men and women perform RT at different %1RM in BP, except for the AC during a RT program utilizing 8–12 RM per set.
Scapular medial border displacement and its relationships to shoulder internal and external rotator muscle function in Division III baseball players
Authors: Hong Junggi , Burfeind Kevin , Chun Jihyun , Van Ryssegem Guido
Published: October 2018

BACKGROUMD: Alteration in scapular medial border displacement often observed as scapular winging, can affect the force couples of the rotator cuff muscles and thereby shoulder function. The relationship between scapular medial border displacement and shoulder internal and external rotator muscle function in the baseball player-throwing arm has not been studied.

OBJECTIVE: The purpose of the study was to determine if any relationship exists between the amounts of scapular medial border displacement measured at rest and during the sitting hand press up test position and shoulder internal and external rotator muscular strength in Division III baseball players throwing arm.

METHODS: A total of 51 Division III baseball players volunteered for the study. Scapular medial border displacement was measured with a standardized posterior scapular displacement measurement tool in two positions, the resting and the sitting hand press-up position. Isokinetic strength of concentric internal rotation (IR) and external rotation (ER) peak torque and time to peak torque for each subject were measured using 3 maximal testing repetitions at 60°/s.

RESULTS: The results of the study showed a linear relationship between the amount of scapular medial border displacement and concentric IR strength and also in time to peak torque. However, no linear relationships were observed between scapular medial border displacement and other isokinetic strength variables.

CONCLUSIONS: Scapular medial border displacement produced during a loaded state influences shoulder internal rotatory strength. This may bear on rehabilitation and strengthening exercises in terms of focusing on proper scapular position and subsequent muscular balance to optimize shoulder function.
Test-retest reliability of the 30-sec Wingate Cycle Test in a trained male cohort
Authors: Malone John K. , Blake Catherine , Caulfield Brian
Published: October 2018

BACKGROUND: Test-retest reliability of performing 1–2 bouts of a 30 s Wingate (30WanT) has been shown to improve by averaging 2 bouts.

OBJECTIVE: To investigate whether adding a 3rd bout enhanced or decreased reliability.

METHODS: On three occasions, 13 triathletes performed three 30WanT's on a cycle ergometer. Peak power (PP), mean power (MP) and fatigue index (FI) reliability across bouts (Intra-session) and days (Inter-session) were tested. Mean and % change between bouts, typical errors of measurement (TEM) and intra-class correlation co-efficient(ICC) were compared between consecutive pairs of bouts and 3 bouts. Single (1& 2), averaged 2 (Σ 1+2) and 3 bout (Σ 1+2+3) between days using TEMs and ICCs were also compared.

RESULTS: Intra-session ICCs for 2 and 3 bouts for PP, MP and FI showed strong reliability (> 0.7). Three bouts had lower TEM for MP, but 2 bouts had less TEM for PP and FI. Inter-session reliability ICCs were > 0.90 for PP, 0.94 for MP and 0.82 for FI for the 1, 2 and 3 bouts with no clear difference between.

CONCLUSIONS: Performing 1, 2 and 3 bouts showed high to very high reliability, with a 3rd bout not clearly reducing TEM, and in some cases introducung more variability.
Muscle isokinetic strength and endurance in short- and long-term type 2 diabetes
Authors: Hatef Boshra , Bahrpeyma Farid , Vaziri Poopak Moatamed
Published: October 2018

BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) are subject to progressive reduction in muscle strength. However, the effect of T2DM and its duration on muscle endurance is not clear yet.

OBJECTIVE: An assessment of force and endurance in short- and long-term diabetes during an isokinetic exercise.

METHODS: The peak torqueof knee flexion and extension was recorded for each cycle of 40 isokinetic repetitions of knee flexion/extension at a velocity of 150°/s. Fifty subjects participated in the study, 18 of whom were diagnosed with diabetes for less than 10 years, 12 subjects with 10 or more years of T2DM and 20 matched healthy control subjects (HC).

RESULTS: The endurance index (EI) and the slope of the knee flexor PT curve indicated that patients with long-term T2DM were significantly more resistant to fatigue in comparison to those with short-term T2DM and even to HC subjects.

CONCLUSION: Long-term diabetes may cause some muscular adaptation to maintain knee flexor muscle performance during intensive short-term activity.
Randomization versus matching method in resistance training research: A simulation study based on maximal isometric squat strength recovery data
Authors: Pekünlü Ekim , Özsu İlbilge
Published: October 2018

BACKGROUND: The randomization method (RM) is used as a gold standard for creating equal groups in most independent-group design studies.

OBJECTIVE: To identify whether the fatigue index (FI)-based matching method could be an alternative for the RM in the context of forming equal independent study groups using relative maximal isometric squat strength(R-MISS) recovery data as the dependent variable.

METHODS: Baseline R-MISS values of 30 resistance-trained male participants were assessed. FI was calculated during an exhaustive training intervention (ETI), including four sets of submaximal isometric squat contractions. Maximal isometric squats were performed 30 seconds, and 2, 4, 6, 8, 10, 12, and 14 minutes after the ETI to assess the recovery levels of R-MISS. For the statistical analyses, low- and high-endurance groups, and two equal-endurance groups (each including 15 participants) were retrospectively formed based on FI scores.

RESULTS: The results of the repeated-measures analysis of variance revealed that recovery moments greatly differed (8 minutes) between the high- and low-endurance groups but were similar between the two equal-endurance groups(difference of 2 minutes). Simulations performed using the resampling procedure revealed that the FI-based matching method was more successful than the RM(71.6% vs. 56.2%) in the context of forming equal study groups.

CONCLUSIONS: These results indicate that the FI-based matching method is a better alternative to the RM for preventing an unequal distribution of participants among independent groups in R-MISS recovery-related studies.
An Isokinetic Estimation of Total Arm Strength
Authors: Schexneider Malton A. , Catlin Pamela A. , Davies George J. , Mattson Paul A.
Published: October 2018

The purpose of this study was to determine upper extremity strength values. Thirty healthy, nonathletic males participated. Bilateral upper extremity isokinetic testing of shoulder, elbow, and wrist occurred at speeds of 60, 180, and 300 deg/sec. Total arm strength (TAS), total arm work (TAW), and total arm average power (TAAP) were calculated for each extremity. A paired t-test was used to compare TAS, TAW, and TAAP values between the dominant and nondominant upper extremities. Statistically significant differences between upper extremities were observed at all three speeds for TAS, TAW, and TAAP. The relationship between body weight and each of the variables of TAS, TAW, and TAAP was statistically significant for TAS and TAW at all three speeds, while TAAP demonstrated a correlation only at 180 deg/sec. Further research is needed in the area of total arm strength.
Consistency of Repeated Isokinetic Testing: Effect of Different Examiners, Sites, and Protocols
Authors: Byl Nancy N. , Wells Laurie , Grady Deborah , Friedlander Anne , Sadowsky Steve
Published: October 2018

Normative data are needed to permit physical therapists to determine if patient measurements of strength are within normal limits. However, to generate normative data, it is essential to evaluate large numbers of subjects. This is only possible with collaboration to pool measurements across different sites with different examiners. This study evaluated the consistency of repeated isokinetic knee flexion and extension measurements with the same subjects tested on the Cybex 340 Extremity Unit with two different examiners at two different sites following the same protocol and then different protocols. The t test was used to determine if the mean difference scores significantly varied from zero (p = .05). Within the same site, following the same protocol, there were no significant differences in measurement by the two examiners for peak torque (at 90, 120, or 180 deg/sec), work in flexion (120 deg/sec) or endurance (120 deg/sec), but there was a significant difference in work extension. By site, there were no significant differences in repeated measurements for peak torque, work, or endurance (120 deg/sec). There were significant differences in peak torque flexion when different protocols were used, even when the same examiner was testing at the same site. The coefficients of variation for the repeated measurements varied from 4.5% to 13.6%. The results from this study suggest that physical therapists from different sites could collaborate to pool data for developing norms for isokinetic knee flexion and extension torque as long as the same test protocol was followed. However, the large variation in retest measurements and the coefficient of variation suggest that when a therapist wants to determine if a patient has made a significant gain in strength, the remeasurement should be taken by the same examiner at the same site. More research is needed to determine if the consistency of isokinetic torque testing with different examiners and different sites is equally high for other muscle groups and with other types of isokinetic dynamometers.
The Relationship of Electromyographic Activity and Force of the Vastus Medialis Oblique and Vastus Lateralis Muscles During Maximal Isometric Knee Extension Contractions
Authors: Fiebert Ira M. , LeBlanc William G. , McGuane Sheila A. , Schnoes Cynthia D. , Strickland Kathryn M.
Published: October 2018

We examined the relationship between the vastus medialis oblique (VMO) and the vastus lateralis (VL) during maximal isometric knee extension contractions by measuring force and electromyographic (EMG) activity of the two muscles at 45 and 90 deg of knee flexion. Testing involved three maximal isometric contractions at the two positions for 27 subjects (50 legs). Recordings of average EMG and force output were measured by the Bio-Prompt 3000 and the FARO Axis Muscle Tester, respectively. The results showed these statistically significant differences pertaining to EMG activity: (1) greater VL at 45 deg for the whole sample; (2) greater VMO and VL in males at 45 deg; (3) greater VMO in females at 90 deg; (4) greater VMO and VL in males than in females at 45 deg; and (5) a correlation of VMO and VL in females at 45 deg. These results demonstrate that sex differences exist in EMG activity between the VMO and VL at two angles of knee extension.
Comparison of Quadriceps Peak Torque Using Three Different Isokinetic Dynamometers
Authors: Greenberger Hilary B. , Wilkowski Todd , Belyea Barbara
Published: October 2018

The purpose of this study was to investigate concentric quadriceps peak torque value using the Cybex II (Cybex, Ronkonkoma, NY), Biodex B-2000 (Biodex, Shirley, Ny) and Kinetic Communicator (KinCom; Chattex, Hixson, TX) 500H. Fourteen subjects (average age 20.14±0.36 years) were tested on their dominant leg on each of the three devices. This study concentrated on two sets of data: (1) highest peak torque, comparing the highest concentric peak torque value produced on each machine; and (2) clinical peak torque comparing the highest peak torque values produced on the Cybex and Biodex with the mean peak torque for the given number of repetitions performed on the KinCom. Subjects were randomly assigned to begin testing on one of the three machines. At least 72 hours of rest occurred between each of the three testing sessions. Subjects first warmed up on a stationary bike for 5 minutes. Subjects then warmed up on the isokinetic device at approximately 25% maximal effort. Three concentric maximal effort extensions were then performed (60 deg/sec). After a minute of rest, each subject was instructed to perform three more concentric maximal effort extensions which were used in the data collection. The speed was increased to 240 deg/sec and the same procedure was followed. Analysis of variance (AN OVA) and posthoc results comparing raw data showed a significant difference between all devices at 60 deg/sec. At 240 deg/sec a significant difference was only noted between the Cybex and Biodex. ANOVA and posthoc tests comparing clinical data at speeds of 60 and 240 deg/sec showed a significant difference when comparing the Biodex to either of the other two dynamometers. Pearson product-moment correlation coefficient ranged from 0.84 to 0.97. This result indicated a strong relationship between the three dynamometers. The authors concluded that caution should be used when comparing the results from one isokinetic dynamometer to the results of a different model dynamometer.
The Effect of Deleting Nonisokinetic Phases of Movement from Isokinetic Strength Evaluations
Authors: Hoens Alison M. , Strauss Geoffrey R.
Published: October 2018

The isokinetic strength and endurance of the trunk extensors and flexors in 72 normal male and female subjects were evaluated concentrically from 25° of extension to 30° of flexion at angular velocities of 20, 40, and 60 deg/sec, on two occasions. Full range of motion (ROM) average torque (FRAT) and truncated ROM average torque (TRAD were calculated. The direct values and derived ratios were analyzed by repeated-measures analysis of variance and Pearson product moment correlations. Direct FRAT and TRAT measures, although highly correlated (r > 0.997), were significantly different (p = 0.000) at each of the three angular velocities. Derived agonist/antagonist ratios had slightly lower correlations (r > 0.980) and were significantly different from each other only at 40 and 60 deg/sec (p = 0.0001 and p = 0.0012). It was concluded that for measurements of isokinetic strength of TEs and TFs, the initial and terminal nonisokinetic phases should be truncated before calculating the average torque, unless the result is expressed as the agonist/antagonist ratio and the angular velocity of measurement is slow.
Eccentric and Concentric Torque Production of the Knee Extensors in Endurance Runners and Cyclists
Authors: Kovaleski John E. , Heitman Robert J. , Ficca Matthew H.
Published: October 2018

Problems during the deceleration phase of running include muscle trauma and eccentric force deficits caused by a maladaptation within the nervous system. Eccentric muscle dysfunction should be greater in runners than in cyclists because cycling does not involve weight-bearing repetitive deceleration. Therefore, we compared the endurance of runners and cyclists for eccentric torque production across velocities to determine if the eccentric torque-velocity relationship of cyclists was different than that of runners. Ten endurance runners and 10 endurance cyclists were tested for isokinetic eccentric and concentric knee extension peak torque (PT) at 30, 90, 150, and 210 deg/sec (0.52, 1.57, 2.62, and 3.66 rad/sec). The cyclists produced (p≤0.05) greater concentric and eccentric PT. Eccentric and concentric PT were different across velocities (p≤0.05), but the type of exercise by velocity interaction was not different (p≥0.05). In addition, a significant linear trend (p≤0.05) was noted across velocities for concentric PT for both runners and cyclists. Thus, as velocity increases, a significant decrease is seen in concentric PT. No increase or decrease in eccentric PT (p≥0.05) across the four velocities was observed in either runners or cyclists. We conclude that eccentric PT is greater than concentric PT and that eccentric PT does not change as velocity increases. Therefore, the type of exercise, whether highly decelerative or not, does not influence the shape of the eccentric torque-velocity relationship. The lack of change in eccentric PT with increasing velocity may be due to a neural mechanism that is activated during maximal contractions to help ensure a safe maximum tension level.
Co-activation of quadriceps and hamstring muscles during concentric and eccentric isokinetic exercise
Authors: Donne B. , Luckwill R.G.
Published: October 2018

The purpose of this study was to investigate co-activation of the quadriceps and hamstring musculature during concentric and eccentric isokinetic actions at 30° s−1. Eight female sedentary subjects performed maximal concentric and eccentric knee flexion/extension actions on an isokinetic dynamometer while simultaneous recordings of moment, joint position and agonist/antagonist electromyographic (EMG) activity from the rectus femoris and semitendinosus muscles were computer processed. Mean integrated electromyographic (IEMG) activity for agonist and antagonist muscle groups and mean moment data were calculated for three discrete knee angle ranges; outer (25–34°), mid (45–54°) and inner (65–74°) for both concentric and eccentric actions. Individual IEMG activity was corrected to account for background activity in the unstressed muscle at 30°, 50° and 70° of knee flexion/extension. The results of this study show that under concentric and eccentric actions the hamstrings were more active during knee extension than the quadriceps were during knee flexion at all angle ranges studied. The corrected mean per cent IEMG activity of the co-contracting hamstrings throughout the joint range were 14 and 21% for concentric and eccentric actions respectively, for co-contracting quadriceps these values were 2.5 and 3.5% respectively. All per cent IEMG values were expressed as a percentage of the same muscle group and action (shortening/lengthening) during agonist action. No significant difference was seen between concentric and eccentric co-contraction per cent IEMG activity at any knee angle range studied. The data suggests that the hamstrings are used to a much greater extent than the quadriceps for limb deceleration and that in particular, hamstring antagonist muscle tension should be considered when analysing agonist quadriceps isokinetic moment curves.
Strength profile of major muscle groups
Authors: Bober Tadeusz
Published: October 2018

The goal of the paper is to outline the topography of the strength of major muscle groups and to investigate the flexion:extension ratios in the joints of upper and lower extremities. There are number of papers undertaking different aspects of muscle strength — particularly concerning elbow flexors and knee extensors but there is only limited investigation on a sufficient number of muscle groups of one population, which would make it possible to outline the strength topography. For this purpose, the measurement of static torque of the flexors and extensors of elbow, shoulder, knee and hip joints was carried out. Twenty-two students not practising sport were tested on a Merac machine. Some data of other authors on children and athletes is included for comparison. The relationship between the strength of muscle groups and body mass turned up to be non-linear. The similarities of the strength profile of the student group as compared with selected data of children and athletes are discussed. The flexion:extension ratios in some joints are quite different between groups, which is possibly — among other factors — due to different procedures applied.
Anterior tibial translation related to isokinetic concentric quadriceps torques
Authors: Antonopoulos J. , Gillquist J.
Published: October 2018

Sagittal translation of the tibia was examined in a static test with 90 N force at 20° of knee flexion and dynamically during knee extension in a Biodex machine using increasing quadriceps torque in six healthy volunteers. The translation increased in a non-linear fashion with increasing torque. Similar relative increases in quadriceps torque caused similar relative increases in translation in the different individuals. The dynamic translation at the individual maximum quadriceps torque was equal to the static 90-N translation. There was a negative correlation between the maximum quadriceps torque and the static 90-N translation. The results indicate that the quadriceps torque is related to the amount of translation in the knee joint possibly by some feed back mechanism from the ligaments preventing abnormal translation. The findings also imply that a limitation of quadriceps torque around 80% of maximum would limit the strain in an injured ligament to a level not higher than what is caused by normal laxity measurements.
Gender specificity in the age-related decline of strength: concentric versus eccentric
Authors: Bellew James W. , Malone Terry R. , Nitz Arthur J. , Hart Anne L.
Published: October 2018

Objective: To assess gender specific differences in the decline of quadriceps strength under concentric and eccentric conditions. Design: Sixty volunteer subjects clear of musculoskeletal pathology were gender matched to three age groups (20-29, 40-49 and 60-69) with ten subjects in each gender-age group. Subjects performed concentric and eccentric knee extension at 60o. s-1 and 120o . s-1 on a Cybex 6000 isokinetics dynamometer. Strength was measured as peak torque (PT) as a percentage of gross body weight. The rate os strength decline between genders at each contraction type and angular velocity was expressed by plotting regression lines and comparing slopes for significant difference. Results: Eleven of twelve inter- and intragender comparing of stregth decline failed to reveal significance with either angular velocity or contraction type (p = 0.09- 0.97). However, unlike the males, females revealed a more significant rate of decline in eccentric strength than with concentric at 120 o .s-1 (p < 0.05). Intergender comparison of concentric strength at 120 o .s -1 was insignificant difference between genders, female displayed a more precipitous rate of decline in eccentric strength than concentric. Furthermore, but statistically insignificant at p = 0.09, males appear to lose concentric strength at a greater rate than do females at the faster angular velocity.
Characteristics of the shift from the fatigue phase to the endurance level (breakpoint) of peak torque during repeated dynamic maximal knee extensions are correlated to muscle morphology
Authors: Gerdle Bjorn , Karlsson Stefan , Crenshaw Albert G. , Fridén Jan , Nilsson Lennart
Published: October 2018

During dynamic (isokinetic) maximal contractions the mechanical output will decrease steeply during the initial 20--60 contractions (the fatigue phase) followed by a stable level (the endurance level). From visual inspections it is obvious that the breakpoint between these two phases differs between individuals. Based upon regression techniques we have investigated two variables of interest with respect to the breakpoint: the number of contractions (Bp-no) before the breakpoint and the angle (o) between the two phases (Bp-deg). We also investigated the interrelationship between output, sex, muscle morphology, and the two variables of the breakpoint during maximal dynamic knee extensions. Twenty clinically healthy subjects (11 males and 9 females) participated. Muscle biopsies of vastus lateralis were obtained from 19 out of 20 subjects. Bp-no was found at 42 ± 14 contractions (no sex difference). A significant difference p=0.001 between the two sexes was found for the Bp-deg (males: 100 pm 14 vs. females: 12 pm 16. No significant correlation existed between Bb-no and Bp-deg. Bp-deg and initial peak torque mainly correlated with the fibre areas. Bp-deg could be predicted in a model with sex and fibre areas as significant variables. The slope and endurance level (absolute and relative) of peak torque and Bp-no correlated negatively with % type 2b. Analyses of the relationship between output and morphology showed that different morphological variables (area or proportions) were of significant importance in different stages of the endurance test. In conclusion a method for determination of the breakpoint has been presented. The two variables presented correlated with important physiological aspects.
Relationship between peak moment, power and work corrected for the influence of inertial effects
Authors: Iossifidou Anna N. , Baltzopoulos Vassilios
Published: October 2018

Moment measurements in isokinetic dynamometry are influenced by moments due to acceleration. The purpose of the present study was to examine the inertial effects on peak moment, power and work during concentric isokinetic knee extension at 60, 180 and 300 deg/s. Seven healthy young adults participated in the present study. Angular displacement from the Biodex software was used to calculate angular velocity and acceleration. A recursive second-order Butterworth filter was applied on angular displacement data and a cut-off frequency of approximately 5 Hz was used based on power spectrum assessment. Finally the actual joint moment was calculated by taking into account the moments due to acceleration of the limb-lever arm system. In general the correlations between the examined parameters were not influenced by inertial effects. A weak relationship between peak moment and power was found at 300 deg/s. Furthermore the differences between dynamometer moment and the moment corrected for the inertial effects increased as the preselected angular velocity increased. At 300 deg s the dynamometer moment was 8.12% higher than the calculated joint moment. Absolute values of work measurements were similar before and after correction but work production was different during the initial acceleration and the final deceleration periods. Based on our findings it was concluded that corrections for inertial effects are essential during moment, work and power measurements at high velocities in isokinetic dynamometry. Finally, work and power should not be replaced by peak moment because they depend on both the range of motion and the moment development throughout the range of motion and therefore offer additional information concerning muscle and joint function.
Predicting 1-RM isotonic knee extension strength utilizing isokinetic dynamometry
Authors: Gulick Dawn T. , Chiappa Jeffrey J. , Crowley Kevin R. , Schade Mark E. , Wescott Scott R.
Published: October 2018

The purpose of this study was twofold: determine which isokinetic determinants correlated best with an isotonic one-repetition maximum (1-RM) and to generate, based on these determinants a formula that will allow clinicians to utilize isokinetic testing to predict an isotonic 1-RM. Fifty female subjects, ranging from 18-35 years of age, participated in this study. Strength measurements using a Cybex II isokinetic dynamometer (peak torque, average peak torque, peak torque:body weight, work per repetition, and total work) and a Cybex isotonic knee extension machine were performed. The subject's height and body weight were recorded. Through linear regression analysis the variables peak torque and body weight were determined to be the best predictors of an isotonic 1-RM. These variables were incorporated in the following formula: Predicted 1-RM = 21.38 + (0.24 x Peak Torque) + (0.18 x Body Weight) which may used utilized by clinicians to predict an isotonic 1-RM.
Measurement of acute dynamic anaerobic muscle fatigue using a novel Fatigue Resistance Index
Authors: Kaminski Thomas W. , Godfrey Michael D. , Braith Randy W. , Stevens Bruce R.
Published: October 2018

A variety of isokinetic fatigue protocols have been previously reported in the literature. The purpose of this study was to examine a new protocol to objectively quantify dynamic concentric and eccentric muscle performance in individuals, or in a multiple subject group, under conditions of acute exhaustive exercise. Pre-fatigue maximal peak torque (PT) and peri-fatigue PT values were measured in unilateral dominant leg quadriceps femoris of human subjects using an isokinetic dynamometer. The protocol was based on single-velocity (90 $^{\circ}$ /s) reciprocal-mode concentric/eccentric (CON/ECC) contractions fixed at 35 repetitions per set. A novel ``Fatigue Resistance Index'' (FRI) was then calculated for each individual subject for both CON and ECC contractions. The group CON FRI( $36.5 \pm 3.9$ % maximal force) was greater than group ECC FRI( $26.9 \pm 2.7$ % force). This protocol and FRI permit comparisons between eccentric and concentric dynamic anaerobic muscle performances for a given individual subject, or for a group of subjects.
The effects of ice immersion on concentric and eccentric isokinetic muscle performance in the ankle
Authors: Hatzel Brian M. , Kaminski Thomas W.
Published: October 2018

The purpose of this study was to determine the effects of cryotherapy on isokinetic ankle strength immediately after ice immersion treatment. Concentric (CON) and eccentric (ECC) isokinetic ankle strength was measured on 20 male subjects using a Kin Com 125 AP (Chattanooga Group, Hixson, TN) isokinetic dynamometer. Plantar flexion, dorsiflexion, inversion and eversion motions were assessed at speeds of 60 $^{\circ}$ /s and 120 $^{\circ}$ /s before and immediately after an ice immersion treatment (10 $^{\circ}$ C for 20 $'$ ). Peak torque (PT) values were extracted from the maximal torque curves and used in the data analysis. ECC PT was higher than CON PT at both speeds and was not affected by ice immersion treatment. The only notable finding was a significant main effect for test (PRE vs. POST) for CON dorsiflexion ankle strength. The Tukey post hoc test determined that POST test PT values ( $39.7\pm 12.7$ Nm) were significantly lower than PRE test scores( $45.9\pm 11.2$ Nm). This finding suggests that CON dorsiflexion strength in the ankle may be adversely affected immediately after ice immersion application. Clinicians should still exercise caution when allowing athletes to return to competition immediately following ice immersion application to the lower leg.
Effects of bandwidth knowledge of results on the performance and learning of a shoulder internal rotation isokinetic strength task
Authors: Shewokis Patricia A. , Kennedy Christopher Z. , Marsh Jennifer L.
Published: October 2018

The purpose of this study was to examine the influence of no-error knowledge of results (KR) and relative frequency of feedback on the performance and retention of an isokinetic, internal shoulder rotation exercise. Males( $N =32$ ), who were free of any shoulder injuries, uninvolved in organized athletics, and unfamiliar with isokinetic testing; performed 90 acquisition trials over a period of three days at 70% after the last acquisition session followed a 10-trial delayed retention test. Participants received error KR in either a 10% bandwidth, yoked, verbal 100% KR condition. Retention results revealed that participants in the 10% bandwidth and yoked conditions performed more consistently than both of the 100% to be more accurate than their yoked counterparts. Our findings support previous research and provide empirical support for using reduced amounts of extrinsic feedback when learning a sub-maximal, isokinetic strength task.
Torque characteristics of the ankle plantarflexors and dorsiflexors during eccentric and concentric contraction in healthy young males
Authors: Poulis S. , Poulis I. , Soames R.W.
Published: October 2018

The torque characteristics were determined for the ankle dorsiflexors and plantarflexors during concentric and eccentric contractions, at 45 $^{\circ}$ /s with the knee flexed 90 $^{\circ}$ , in 37 young healthy males aged 21 to 24 years. Mean maximum torque during concentric and eccentric contraction was $32.8 \pm 5.5$ Nm and $57.8 \pm 14.3$ Nm(ratio $0.57$ ) for the dorsiflexors, and $86.3 \pm 26.8$ Nm and $86.3 \pm 26.8$ Nm (ratio $0.60$ ) for the plantarflexors. The dorsiflexor/plantarflexor maximum torque ratio was 0.38 and 0.40 for concentric and eccentric contractions. The angle of maximum torque generation was $17.4^{\circ} \pm 13.7^{\circ}$ and $15.7^{\circ} \pm 12.2^{\circ}$ plantarflexion for the dorsiflexors working concentrically and eccentrically respectively. For the plantarflexors the respective angles were $17.0^{\circ} \pm 9.6^{\circ}$ and $23.3^{\circ} \pm 11.4^{\circ}$ plantarflexion: the difference in angle being significant( $p<0.01$ ). The torque characteristics presented in this study provide a standard against which muscle coordination can be determined and the planning of rehabilitation programs set.
Isokinetic profile of patient with anterior cruciate ligament tear
Authors: Benjuya N. , Plotqin D. , Melzer I.
Published: October 2018

The objective of this study was to analyze the performance of knee muscles in the affected and nonaffected sides of ACL patients as well as with healthy asymptomatic subjects. Fifty-four males, 27 with asymptomatic knees and 27 patients with tear in ACL were included in the study. Subjects performed concentric knee extension and flexion efforts at 60\ci/s and 180\ci/s on a Biodex isokinetic dynamometer. Isokinetic peak torque, angle to peak moment of quadriceps (Q) and hamstring (H), and hamstrings/quadriceps ratio (HQR) were measured. There was a significant decline in the mean strength of Q at 60\ci/s for the involved side compared with either the uninvolved side or with that of the healthy subjects, but not in H. There was also a significant decrease in mean Q strength at 180\ci/s of the involved side of ACL patients compared with the healthy young males. There was a significant difference in mean angle to peak moment of Q at 180\ci/s in the healthy group compared with the involved side of the patients and a significant difference for the same parameter in H at 60\ci/s in the involved compared with the healthy group and uninvolved sides of the ACL patients. There was no significant difference in hamstrings/quadriceps ratio between the groups. It was concluded that the effect of ACL tear on H strength is significantly less than that on the Q one year post-injury. Angle to peak moment offers original and practical information for the determination of individual performance in post ACL injury patients.