Isokinetic Eccentric Exercise Research Articles

Walking kinematics and kinetics following eccentric exercise-induced muscle damage

The goal of this investigation was to investigate how walking patterns are affected following muscle-damaging exercise by quantifying both lower limb kinematics and kinetics. Fifteen young women conducted a maximal isokinetic eccentric exercise (EE) muscle damage protocol (5×15) of the knee extensors and flexors of both legs at 60°/s. Three-dimensional motion data and ground reaction forces (GRFs) were collected 24h pre-EE while the participants walked at their preferred self-selected walking speed (SWS). Participants were asked to perform two gait conditions 48h post-EE. The first condition (COND1) was to walk at their own speed and the second condition (COND2) to maintain the SWS (±5%) they had 24h pre-EE. Walking speed during COND1 was significantly lower compared to pre-exercise values. When walking speed was controlled during COND2, significant effects of muscle damage were noticed, among other variables, for stride frequency, loading rate, lateral and vertical GRFs, as well as for specific knee kinematics and kinetics. These findings provide new insights into how walking patterns are adapted to compensate for the impaired function of the knee musculature following muscle damage. The importance to distinguish the findings caused by muscle damage from those exhibited in response to changes in stride frequency is highlighted.

Aging is not a barrier to muscle and redox adaptations: Applying the repeated eccentric exercise model

Despite the progress of analytic techniques and the refinement of study designs, striking disagreement exists among studies regarding the influence of exercise on muscle function and redox homeostasis in the elderly. The repeated eccentric exercise model was applied to produce long-lasting and extensive changes in redox biomarkers and to reveal more effectively the potential effects of aging on redox homeostasis. Ten young (20.6±0.5years) and ten elderly men (64.6±1.1years) underwent an isokinetic eccentric exercise session, which was repeated after three weeks. Muscle function/damage indices (torque, range of movement, muscle soreness and creatine kinase) and redox biomarkers (F2-isoprostanes, protein carbonyls, glutathione, catalase, superoxide dismutase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, uric acid, bilirubin and albumin) were assessed in plasma, erythrocytes or urine pre-exercise, immediately post-exercise and at 2 and 4days post-exercise. As expected, the elderly group exhibited oxidative stress in baseline compared to the young group. Extensive muscle damage and extensive alterations in redox homeostasis appeared after the first bout of eccentric exercise. Noteworthy, the redox responses were similar between the age groups despite their differences in baseline values. Likewise, both age groups demonstrated blunted alterations in muscle damage and redox homeostasis after the second bout of eccentric exercise indicating adaptations from the first bout of exercise. Elderly individuals seem to be well fitted to participate in demanding physical activities without suffering detrimental effects on skeletal muscle and/or disturbances on redox homeostasis. The repeated eccentric exercise model may be a useful and practical physiological tool to study redox biology in humans.

The Effects of Isokinetic Eccentric Resistance Exercise for the Hip Joint on Functional Gait of Stroke Patients

[Purpose] The purpose of this study was to determine the effects of resistance exercise strengthening the hip flexor and extensor muscles on functional gait of stroke patients. [Subjects and Methods] Twenty patients were randomized into two groups. Both groups performed conventional physical therapy for six weeks. The experimental group also performed isokinetic eccentric resistance exercises for the hip flexor and extensor muscles. The hip muscle strength, stair up and down time, TUG time(timed up and go test), and 10 m gait velocity were measured at the baseline, and after 3 weeks, and 6 weeks of treatment. [Results] The experimental showed significant improvements compared to the baseline in hip muscle strength, stair up and down time, TUG time and 10 m gait velocity after 3 and 6 weeks of treatment. After 3 and 6 weeks of treatment, there were gains in hip muscle strength and 10 m gait velocity. The control group showed no significant increase in hip muscle strength, stair up and down time, TUG time or 10 m gait velocity. [Conclusion] We consider that conventional physical therapy contributes to the improvement of functional gait of stroke patients. However, it is more desirable to perform isokinetic eccentric resistance exercises for hip flexor and extensor muscles combined with conventional physical therapy for the improvement of hip muscle strength, stair up and down time, TUG time and 10 m gait velocity.

Exercise-induced muscle damage and running economy in humans.

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15–30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO2max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO2max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE.

No adverse effects of statins on muscle function and health‐related parameters in the elderly: An exercise study

The aim of the present study was to investigate the effects of a repeated bout of eccentric exercise on health-related parameters and muscle performance on subjects undergoing atorvastatin therapy. Twenty-eight elderly men participated in the investigation and were assigned either in a control (n = 14) or in a statin therapy group (n = 14). All participants performed two isokinetic eccentric exercise bouts separated by 3 weeks. Muscle damage indices, resting energy expenditure, substrate metabolism, lipid and lipoprotein profile, as well as insulin sensitivity, were evaluated before and after eccentric. No differences in muscle function were observed between the two groups either at rest or after exercise. Eccentric exercise increased resting energy expenditure, increased fat oxidation, improved lipid profile, and increased insulin resistance 2 days after both eccentric exercise bouts. However, these changes appeared to lesser extent after the second bout. No differences were observed in the responses in the health-related parameters in the control and in the statin therapy group. Eccentric exercise affected similarly the control and the atorvastatin-treated individuals. The present results indicate that atorvastatin-treated elderly individuals may participate in various physical activities, even high-intensity muscle-damaging activities, without negative impact on muscle function and adaptation.

The effect of contraction type on muscle strength, work and fatigue in maximal isokinetic exercise

This study investigated knee extensor muscle strength, work and fatigue level under maximal isokinetic concentric and eccentric exercise. Seventeen male athletes were randomized into two groups and performed 10 sets of 10 maximal isokinetic concentric (N = 8) or eccentric (N = 9) contractions. Knee extensor peak torque and mean torque values per set were 54-121% and 53-133% higher in eccentric compared to concentric exercise, respectively, whereas the percent fall of performance in these variables was more accentuated in concentric exercise. Total work was significantly higher in eccentric exercise (19475 J) than concentric exercise (15758 J), while fatigue index was greater in concentric (36%) than eccentric (18%) exercise. In conclusion, maximal isokinetic eccentric exercise promotes larger overload to knee extensor muscles than its concentric counterpart due to higher torque produced by the muscle group and also thanks to minor muscle fatigue effects.

Muscle architecture and EMG activity changes during isotonic and isokinetic eccentric exercises

The present study aimed to compare muscle architecture and electromyographic activity during isotonic (IT) and isokinetic (IK) knee extensors eccentric contractions. Seventeen subjects were assigned in test and reproducibility groups. During test session, subjects performed two IT and two IK sets of eccentric contractions of knee extensor muscles. Torque, angular velocity, VL architecture and EMG activity of agonist (vastus lateralis, VL; vastus medialis; rectus femoris) and antagonist (semitendinosus; biceps femoris, BF) muscles were simultaneously recorded and averaged on a 5° window. Torque-angle and angular velocity-angle relationships exhibited differences in mechanical load between the IT and IK modes. Changes in muscle architecture were similar in both modes, since VL fascicles length increased and fascicle angle decreased, resulting in a decrease in muscle thickness during eccentric contraction. Agonist activity and BF co-activity levels were higher in IT mode than in IK mode at short muscle lengths, whereas agonist activity was higher in IK mode than in IT mode at long muscle lengths. Differences in mechanical load between both modes induced specific neuromuscular responses in terms of agonist activity and antagonist co-activity. These results suggest that specific neural adaptations may occur after IT or IK eccentric training. This hypothesis needs to be tested in order to gain new insights concerning the most effective eccentric protocols based on whether the objective is sportive or clinical.

A New Device to Study Isoload Eccentric Exercise

This study was designed to develop a new device allowing mechanical analysis of eccentric exercise against a constant load, with a view in mind to compare isoload (IL) and isokinetic (IK) eccentric exercises. A plate-loaded resistance training device was integrated to an IK dynamometer, to perform the acquisition of mechanical parameters (i.e., external torque, angular velocity). To determine the muscular torque produced by the subject, load torque was experimentally measured (TLexp) at 11 different loads from 30° to 90° angle (0° = lever arm in horizontal position). TLexp was modeled to take friction effect and torque variations into account. Validity of modeled load torque (TLmod) was tested by determining the root mean square (RMS) error, bias, and 2SD between the descending part of TLexp (from 30° to 90°) and TLmod. Validity of TLexp was tested by a linear regression and a Passing-Bablok regression. A pilot analysis on 10 subjects was performed to determine the contribution of the torque because of the moment of inertia to the amount of external work (W). Results showed the validity of TLmod (bias = 0%; RMS error = 0.51%) and TLexp SEM = 4.1 N·m; Intraclass correlation coefficient (ICC) = 1.00; slope = 0.99; y-intercept = -0.13). External work calculation showed a satisfactory reproducibility (SEM = 38.3 J; ICC = 0.98) and moment of inertia contribution to W showed a low value (3.2 ± 2.0%). Results allow us to validate the new device developed in this study. Such a device could be used in future work to study IL eccentric exercise and to compare the effect of IL and IK eccentric exercises in standardized conditions.

Neuromuscular and muscle-tendon system adaptations to isotonic and isokinetic eccentric exercise

ObjectiveTo present the properties of an eccentric contraction and compare neuromuscular and muscle-tendon system adaptations induced by isotonic and isokinetic eccentric trainings. SynthesisAn eccentric muscle contraction is characterized by the production of muscle force associated to a lengthening of the muscle-tendon system. This muscle solicitation can cause micro lesions followed by a regeneration process of the muscle-tendon system. Eccentric exercise is commonly used in functional rehabilitation for its positive effect on collagen synthesis but also for resistance training to increase muscle strength and muscle mass in athletes. Indeed, eccentric training stimulates muscle hypertrophy, increases the fascicle pennation angle, fascicles length and neural activation, thus inducing greater strength gains than concentric or isometric training programs. Eccentric exercise is commonly performed either against a constant external load (isotonic) or at constant velocity (isokinetic), inducing different mechanical constraints. These different mechanical constraints could induce structural and neural adaptive strategies specific to each type of exercise. ConclusionThe literature tends to show that isotonic mode leads to a greater strength gain than isokinetic mode. This observation could be explained by a greater neuromuscular activation after IT training. However, the specific muscle adaptations induced by each mode remain difficult to determine due to the lack of standardized, comparative studies.

A standardization method to compare isotonic vs. isokinetic eccentric exercises

The present study aimed to standardize isotonic (IT) and isokinetic (IK) eccentric exercises by equalizing the amount of work and the angular velocity at two intensity levels, to be able to compare specific effects of these exercise modes on the neuromuscular system. Fourteen subjects participated in three test sessions consisting of two IT and two IK sets on a customized isokinetic dynamometer. IT sets were comprised of 8 eccentric contractions of the knee extensors at 120% of the maximal repetition (1RM) in the first two sessions, and 100% in the third session. IK sets were performed at the same mean angular IT velocity and stopped when the amount of work performed corresponded to the IT set. External work, angular velocity and Root Mean Square (RMS) of electromyographic activity of three superficial muscles of the quadriceps femoris were calculated. Results showed concordance of work and angular velocity for each test session. Both modes involved the same number of repetitions at 120% and fewer repetitions in IK mode at 100% of 1RM. Work and RMS values remained steady in all sets. This study allowed the standardization of isotonic and isokinetic eccentric exercises, a first step before determining their specific effects on neuromuscular function.

The Effects of Imagery on Performance and Pain Perception Associated with Delayed-Onset Muscle Soreness

Research has indicated that the use of imagery may aid in recovery from injuries and reduce the perception of pain in athletes during and after competitions. There is little research concerning acute pain and soreness, such as delayed-onset muscle soreness (DOMS). PURPOSE: To determine whether the use of guided imagery for healing will affect soreness, pressure pain threshold (PPT), and performance associated with DOMS. It was hypothesized that those who listen to a healing imagery script would report less soreness, higher pain threshold, and better performance following DOMS than a control group. METHODS: Participants (38) completed two days of testing with 48 hours between them. At the end of the first day, DOMS was induced by performing 6 sets of 15 reps of isokinetic eccentric exercise at -1.05 rad/sec. Each day consisted of tests of soreness, PPT, vertical jump, isokinetics at 6 speeds, and a Wingate test. 20 participants listened to a healing imagery script 10 times within the 48 hours after inducement of DOMS while 18 listened to relaxing music. RESULTS: Perception of muscle soreness was worse for the front and back of the leg (p<.01) regardless of group and the control group reported greater pain perception both before and after the intervention than the imagery group (p<.05). PPT was lower after treatment in the lateral hamstring regardless of group (p<.05). Peak torque for knee extension at 1.05 rad/sec was reduced after treatment for both groups (p<.01). Peak torque for knee flexion at 2.09, 3.14, 5.24, & 6.28 rad/sec was better after treatment for both groups (p<.05) and peak torque for flexion was better at 6.28 rad/sec (p<.05) for both groups. While the Power Drop percentage on the Wingate test appeared better for the imagery group and worse for the control group following treatment, this failed to reach statistical significance (p=.07). CONCLUSION: Healing imagery had no significant impact on perception of soreness, PPT, isokinetic measures, or anaerobic power testing. Based on the actual, but non-significant, changes in power drop results from the Wingate test, it appears that imagery could impact longer duration anaerobic performance as opposed to short duration performance. Further research is needed to determine if healing imagery can improve performance on longer anaerobic and possibly aerobic activities.

The effects of Kinesio-Taping® on quadriceps strength during isokinetic exercise in healthy non athlete women

Purpose: The purpose of the study was to investigate the effect of Kinesio Taping ® on quadriceps strength at maximum concentric and eccentric isokinetic exercise mode in healthy non-athlete women in order to examine the Kinesio taping effect in increasing or decreasing the muscular quadriceps strength. Methods: Three different quadriceps taping modes have been used (no taping, placebo taping, Kinesio-Taping) for the study. and isokinetic concentric and eccentric strength assessments have been done for both knee extensors and flexors. Results: One-way ANOVA for repeated measures revealed no significant differences in max concentric torque between the three different taping modes but significant differences in max eccentric torque during both the concentric and eccentric mode of the quadriceps muscle. Conclusion: The results suggest that application of Kinestio Taping on the anterior surface of the thigh, in the direction of vastus medialis, laterallis and rectus femoris fascia, could increase the eccentric muscle strength (isokinetic eccentric peak torque), in healthy adults.

Impact Of Protease Supplementation On Pain Perception And Exercise Affect During Cycle Ergometry With DOMS

Delayed onset muscle soreness (DOMS) is a common occurrence following intense exercise. It has been suggested that protease supplementation may diminish the effects of DOMS. Additionally, feelings of soreness may adversely impact exercise affect. PURPOSE: To examine the effects of protease supplementation on the perception of pain (PP) and exercise affect following the onset of DOMS. METHODS: This study used a matched-pairs design. Twenty-four participants (12 males: Mean BMI = 24.7 ± 2.1; 12 females; Mean BMI = 20.8 ± 2.3) participated in this investigation. DOMS was induced by performing 6 sets of 10 reps of isokinetic eccentric exercise (EE) at -1.05 rad/sec. Each participant took either 2 protease tablets (PRO) or a placebo (PLAC) 4 times a day for 4 days (from 24 H pre-EE to 48 H post-EE). Supplementation was blinded and randomized. Each participant performed 2 identical, 35 min exercise sessions on a cycle ergometer, one pre-EE and one 2 days post-EE. Intensity for the exercise sessions was set during the initial session by asking each participant to exercise at a "13“ on the Borg RPE scale. The ergometer resistance was recorded and used during the post-EE exercise session. Every 5 minutes during the exercise sessions, PP was assessed using Borg's CR-10 scale and affect was measured using the feeling scale (FS) and the felt-arousal scale (FAS). Results were analyzed using a repeated-measures GLM. RESULTS: No differences were seen between the groups for PP, FS, or FAS during the pre-EE exercise session. Differences were seen for PP at the 5, 25, 30, and 35 minute mark of the post-EE exercise session with the PRO reporting less discomfort than the PLAC (p<0.05). A significant difference was seen for FS with the PRO reporting greater feelings of pleasantness than the PLAC at the 20, 25, 30 and 35 minute mark of the post-EE exercise session (p<0.05). A trend was seen for PP at the 20 minute mark (p= 0.07). No differences were seen between the groups for FAS. CONCLUSION: Protease supplementation may positively influence an individual's responses to exercise following DOMS. This finding may be important in planning exercise programs, especially when considering return to activity following an intense exercise session. This work was supported through funding by Enzymatic Therapy Inc., Green Bay, WI.

Time-of-day effects during acute isokinetic exhaustive eccentric exercise: Serum leptin response

Circadian rhythms are known to influence muscular performance and regulate leptin hormone secretion, which assists in the regulation of body weight and energy homeostasis. In this study we examined the time-of-day effect on skeletal muscle eccentric contractile properties and the response of serum leptin to acute eccentric exhaustive isokinetic exercise. Male subjects (n = 26) performed a bout of exhaustive eccentric exercise on an isokinetic dynamometer in the morning or late afternoon time on different days. The test was repeated after 7-10 days at different time-of-day. Blood samples were collected at baseline and immediately after exercise for determination of serum leptin. Leg extensor muscle torque and work parameters were recorded, and compared with the time-of-day. Maximal eccentric torque values were not significantly affected by time-of-day. The maximal work performed during single repetition as well as total work values were significantly higher in the afternoon time. Leptin levels significantly decreased after exercise, but no time-of-day effect on serum leptin could be observed. Diurnal variations during short-term isokinetic exhaustive eccentric exercise seem to reflect muscle work capacity, with higher contractile efficiency towards the evening time. Although short-term exhaustive eccentric exercise decreased serum leptin, the levels did not to have a significant diurnal variation.

Isokinetic Eccentric Exercise of Quadriceps Femoris Does Not Affect Running Economy

The purpose of this study was to investigate whether running economy is affected by isokinetic eccentric exercise designed to cause muscle damage. Twenty-four young healthy men performed 120 maximal voluntary eccentric actions at each thigh's quadriceps muscle at an angular velocity of 60 degrees .s. The participants were then randomly divided into 2 equal groups, 1 of which exercised 24 hours later, while the other group rested. Muscle damage indicators (i.e., serum creatine kinase, delayed onset muscle soreness, and eccentric, concentric, and isometric peak torque) and running economy indicators (i.e., oxygen consumption, pulmonary ventilation, respiratory exchange ratio, respiratory rate, and heart rate during treadmill running at 2.2 and 3.3 m.s) were assessed prior to and 48 hours following the eccentric exercise. All muscle damage indicators changed significantly in both groups (p < 0.05) in a way suggestive of considerable muscle damage. Running economy indicators of the exercise group demonstrated only an elevation of respiratory rate at 48 hours (p < 0.05) and a tendency to lower economy compared to the resting group. It can be concluded that isokinetic eccentric exercise applied to the quadriceps femoris muscles did not affect running economy 48 hours later and that resting during this period tended to result in more economical running compared to exercising at 24 hours.

Isokinetic eccentric exercise can induce skeletal muscle injury within the physiologic excursion of muscle-tendon unit: a rabbit model.

Background and PurposeIntensive eccentric exercise can cause muscle damage. We simulated an animal model of isokinetic eccentric exercise by repetitively stretching stimulated triceps surae muscle-tendon units to determine if such exercise affects the mechanical properties of the unit within its physiologic excursion.MethodsBiomechanical parameters of the muscle-tendon unit were monitored during isokinetic eccentric loading in 12 rabbits. In each animal, one limb (control group) was stretched until failure. The other limb (study group) was first subjected to isokinetic and eccentric cyclic loading at the rate of 10.0 cm/min to 112% (group I) or 120% (group II) of its initial length for 1 hour and then stretched to failure. Load-deformation curves and biomechanical parameters were compared between the study and control groups.ResultsWhen the muscle-tendon unit received eccentric cyclic loading to 112%, changes in all biomechanical parameters – except for the slope of the load-deformation curve – were not significant. In contrast, most parameters, including the slope of the load-deformation curve, peak load, deformation at peak load, total energy absorption, and energy absorption before peak load, significantly decreased after isokinetic eccentric cyclic loading to 120%.ConclusionWe found a threshold for eccentrically induced injury of the rabbit triceps surae muscle at between 12% and 20% strain, which is within the physiologic excursion of the muscle-tendon units. Our study provided evidence that eccentric exercise may induce changes in the biomechanical properties of skeletal muscles, even within the physiologic range of the excursion of the muscle-tendon unit.

Análise da resposta da freqüência cardíaca durante a realização de exercício isocinético excêntrico de grupamento extensor de joelho

Analysis of Heart Rate Response During Eccentric Isokinetic Exercise of Knee Extensor Muscle Group Objective: To investigate heart rate response magnitudes during eccentric isokinetic exercise of the knee extensor muscles, at different angular velocities. Method: Ten healthy and active young volunteers underwent maximum eccentric contraction of the extensor muscle group of the dominant knee. An isokinetic dynamometer was used at velocities of 30°/s, 60°/s and 120°/ s, randomly sequenced. The heart rate (HR) was obtained beat-by-beat, using a modified MC5 electrocardiogram lead, over 60s within the contraction, with five repetitions for each angular velocity, and over 120s after exercise effort. Mean HR for the 60s pre-exercise interval, peak HR attained at the end of exercise effort, HR variation (ΔHR) and peak torque were calculated. In addition, the pre-exercise mean HR over six minutes was compared with the recovery-period mean HR over six minutes. The results were compared using the Friedman and post hoc Dunn tests. The significance level was set at 5%. Results: No statistically significant differences were observed among the median values of resting HR (68bpm for 30°/s and 60°/s, 70bpm for 120°/s), peak HR (107 bpm for 30°/s, 103bpm for 60°/s and 100bpm for 120°/s), ΔHR (37bpm for 30°/s, 35bpm for 60°/s and 27bpm for 120°/ s) and peak torque (209.5N/m for 30°/s, 217.2N/m for 60°/s and 210.6N/m for 120°/s). The median HR values before and after exercise effort were the same (67bpm). Conclusion: The HR response magnitudes during eccentric muscular activity were similar, which indicates that the cardiac overload was the same for all the angular velocities studied.

Renforcement musculaire isocinétique excentrique des ischiojambiers chez des patients atteints de sclérose en plaque

Objective. – To assess the benefit of a program of rehabilitation involving eccentric isokinetic muscle strengthening for hamstrings of patient with multiple sclerosis. Patients and Methods. – A total of 28 patients with multiple sclerosis and abnormalities when walking who underwent a program of rehabilitation involving eccentric isokinetic muscle strengthening associated with classical neurological rehabilitation. Assessment was by use of an isokinetic test, clinical examination and score on a visual analog scale (VAS) about quality of walking at the beginning and end of the rehabilitation program and three months later. The rehabilitation program involved eccentric isokinetic exercises during 12 sessions. Results. – Patients with multiple sclerosis and difficulty walking showed weak hamstrings on manual muscular testing. After 12 sessions of isokinetic eccentric rehabilitation, hamstring and quadriceps strength increased, VAS score increased, and recurvatum of the knee improved in 26 cases. Three months later, the score for quality of walking remained the same, but that for strength returned to a previous level. Conclusion. – Hamstring strength in patients with multiple sclerosis can be improved without complication with use of eccentric isokinetic rehabilitation. This is an interesting way to improve the quality of walking in these patients.

Manual massage effect in knee extensors peak torque during short-term intense continuous concentric–eccentric isokinetic exercise in female elite athletes

Manual massage is considered an important part of athletic rehabilitation or preparation for training and competition. Objective: To study the possible effects of manual massage on concentric and eccentric peak torque of knee extensors, when applied during intervals of exercise. Methods: Twelve elite female Tae Kwon Do athletes were tested twice during a week (different extremity each) in continuous concentric/eccentric isokinetic exercise (6 sets of 10 repetitions, with 2 minutes intervals). Manual massage was applied during breaks to the extremity (massage extremity) while for the other limb (control extremity) the interval was passive. For both groups peak torque was measured 3 minutes after the last set. The same test was performed 3 minutes prior to the first set. The best performance was recorded pre- and post-exercise and the results were compared. Results: For both groups peak torque (concentric and eccentric) was reduced after the exercise protocol. In the massage group the reduction was lower and significantly different for eccentric type of muscle work ( p< 0.05). Conclusions: Application of manual massage during isokinetic exercise intervals has an enhancing effect on the peak eccentric torque of the knee extensors.

8주간의 등속성 운동프로그램이 만성발목관절 염좌 상해를 입은 운동선수의 근기능 회복에 미치는 영향

The purpose of this study was to identify the effects of isokinetic exercise programs on the muscular function recovery of athletes with ankle sprain. The subjects were 12 male college athletes with chronic ankle sprain assessed by maximum inversion stress roentgnography. 12 participants were randomly assigned into two different treatment groups; concentric isokinetic exercise(CIE, n=6) and eccentric isokinetic exercise(EIE, n=6). The CIE group performed concentric contractions of each ankle dorsiflexor and plantarflexor muscles and the EIE group performed eccentric contractions of each ankle muscle group three days for eight weeks. The instrument was used a spectrum of angular velocities ranging from 30℃/sec intervals and EMG to record activity of tibialis anterior and gastrocnemius, for involved side. The results of this study were following as: 1. Muscular function 1) Dorsiflexors CIE group showed increases(p.05) in peak torque However, both training groups did not display these marked changes in the uninvolved side after the 8-week period. 2) Plantarflexors EIE group showed marked increases(p.01) in peak torque but CIE group didn`t increase in the involved side. In addition, both training groups did not display these marked changes in uninvolved side after the 8-week period. 3) Ⅳ/UV ratio of dorsiflexior CIE group showed marked decreases(p.01) in the Ⅳ/UV ratio of dorsiflexior. However, EIE group did not display these marked changes after the 8-week period. 2.EMG EIE group showed marked increases(p.01) in the gastrocnemius. However, both training groups did not display marked changes in other sides after the 8-week period. These results also indicated that the same eccentric isokinetic exercise as concentric isokinetic exercise; however, the improvements in the Ⅳ/UV ratio of dorsilflexior were better in the CIE group compared with the EIE group after train training. The findings of these results implied that with isokinetic exercise programs used in this study, it is possible to recover muscular function in athletes with chronic ankle sprain. It was also indicated that extensive training involving a high number of repetitions and eccentric contractions was safe, effective, and well tolerated for the athletes with chronic ankle sprain.