Quadriceps Training Research Articles

Unilateral Eccentric Strength Training of the Human Quadriceps: Effect of Loading on Muscle Strength and Size

Eccentric resistance training is effective at increasing muscular volume, force and power production. Eccentric contractions cause augmented myofibrillar tearing leading to greater potential for trained musculature to enhance repair. However, it is unclear what eccentric training protocol is most effective at stimulating significant physiological adaptations related to volume, force and power. PURPOSE: To examine the effect of variable eccentric resistance training loads on parameters of muscular fitness in the human quadriceps. METHODS: Maximum voluntary contraction (MVC), thigh circumference (TC), and strength-to-lean body mass ratio (MVC:LBM) were assessed in nineteen college-aged adults (six men, thirteen women) who completed eight weeks of unilateral strength training of the knee extensors. Subjects were randomly assigned to one of four training groups: eccentric high (EH, 90% 1-RM, N = 5), eccentric medium (EM, 70% 1-RM, N = 6), eccentric low (EL, 50% 1-RM, N = 4), or control (CON, concentric contractions at 50% 1-RM, N = 4). Subjects in each group performed four sets of ten repetitions, two times per week, for eight consecutive weeks. MVC, TC and MVC:LBM were measured before and after the eight week training program. RESULTS: There were no significant differences between trained and untrained legs for any measure (P > 0.05). However, when trained leg group comparisons of MVC and MVC:LBM change were made, EH (26 ± 14 vs. 51 ± 31 N, 0.53 ± 0.20 vs. 0.98 ± 0.41 N/kg) showed a significantly greater increase at post-testing compared to EM (42 ± 8 vs. 47 ± 7 N, 0.72 ± 0.17 vs. 0.81 ± 0.16 N/kg), EL (65 ± 10 vs. 64 ± 11 N, 1.10 ± 0.08 vs. 1.06 ± 0.09 N/kg), and CON (36 ± 8 vs. 36 ± 9 N, 0.77 ± 0.17 vs. 0.73 ± 0.20 N/kg) groups (P < 0.05). CONCLUSIONS: Our findings indicate that training at a relatively high load (90% 1-RM) is more effective than training at lower loads for increasing knee extensor force production, independent of any significantly correlated changes in whole-muscle size, over eight weeks of unilateral eccentric strength training of the quadriceps. However, because trained and untrained legs within groups exhibited similar increases in strength after the training period, the results are inconclusive.

Tibial translation and muscle activation during rehabilitation exercises 5 weeks after anterior cruciate ligament reconstruction

The aim of this study was to compare different rehabilitation exercises with respect to dynamic anterior tibial translation and muscle activation 5 weeks after an anterior cruciate ligament (ACL) reconstruction. Another aim was to compare the ACL-reconstructed knee with the ACL-injured and the uninjured knees for differences in anterior tibial translation and muscle activation during the exercises. Sagittal tibial translation and muscle activation were measured during the Lachman test (static translation) and during seven rehabilitation exercises (dynamic translation) in 19 patients. Results obtained 5 weeks after ACL reconstruction were compared with those obtained before the ACL reconstruction (ACL-deficient and uninjured knee). After ACL reconstruction the seated knee extension produced more anterior tibial translation than the straight leg raise and standing on one leg. The ACL reconstruction reduced the static and the dynamic tibial translation and the tibial translations measured in ACL-reconstructed knees were similar to those measured in uninjured knees. After ACL reconstruction, the patients used a joint stiffening strategy that used more hamstring activation and reduced the dynamic tibial translation. Although all exercises tested are suitable for rehabilitation after ACL reconstruction, to protect the graft from excessive strain, the straight leg raise and squat on one leg are preferable for quadriceps training in the early phase of rehabilitation.

Peak torque and knee kinematics during gait after eccentric isokinetic training of quadriceps in healthy subjects

Objective: To evaluate the effects of eccentric isokinetic training on knee range of motion (ROM) of healthy subjects. Methods: The knee extensor and flexor isokinetic peak torques and ROM of flexion/extension and varus/valgus knee movements during gait of 18 healthy men (21.7r2.2 years; 1.73r0.10m; 68.7r9.4kg; body mass index: 22.6r2kg/m 2 ) were analyzed, before and after six weeks of bilateral eccentric isokinetic training of the knee extensors at 30 o /s. Results: The knee extensor torque increased in both limbs (right, from 229r54 to 304r53Nm; p<0.01; and left, from 228r59 to 311r63Nm; p<0.01), without any difference in torque gain between them. The knee flexor peak torque increased (from 114r30 to 123r22Nm; p<0.05), but the hamstrings/quadriceps (H/Q) ratio decreased (from 0.5r0.08 to 0.39r0.07; p<0.01) after the training. There were no differences in the flexion/extension and varus/valgus movements after the training, except for a small change (4°) in valgus for the left knee. Conclusions: The eccentric isokinetic training of the knee extensors increased the extensor torque and decreased the H/Q ratio, although the effect on the gait pattern seemed negligible in healthy subjects. Associated training for flexors, complementary to the extensor training, seems to be necessary for balance between knee agonists and antagonists. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number: 12607000590460.

The 12-week progressive quadriceps resistance training improves muscle strength, exercise capacity and quality of life in patients with stable chronic heart failure

Background Abnormalities in the skeletal musculature underlie exercise intolerance in chronic heart failure (CHF). We investigated, whether in CHF selective resistance training without accompanying aerobic regime favourably affects muscle strength, muscle mass and improves exercise capacity. Methods Ten patients with stable ischaemic CHF in NYHA class III (9 men, age: 70 ± 6 years [mean ± SD], left ventricular ejection fraction: 30 ± 5%, peak oxygen consumption [peak VO 2]: 12.4 ± 3.0 mL/min/kg) underwent the rehabilitation programme which consisted of a 12-week training phase (progressive resistance exercises restricted to the quadriceps muscles) followed by a 12-week detraining phase. Results All subjects completed a training phase of the programme with no adverse events. Resistance training markedly increased quadriceps strength (right leg: 260 ± 34 vs. 352 ± 28 N, left leg: 264 ± 38 vs. 342 ± 30 N, both p < 0.01 — all comparisons: baseline vs. after training), but did not affect lean tissue mass of lower extremities (both p > 0.2). It was accompanied by an improvement in clinical status (all NYHA III vs. all NYHA II, p < 0.01), quality of life (Minnesota questionnaire: 44 ± 15 vs. 33 ± 18 points, p < 0.05), exercise capacity assessed using a distance during 6-minute walk test (6MWT: 362 ± 83 vs. 455 ± 71 m, p < 0.01), but not peak VO 2 ( p > 0.2). Plasma NT-proBNP remained unchanged during the training. At the end of detraining phase, only a partial improvement in quadriceps strength ( p < 0.05), a 6MWT distance ( p < 0.05) and NYHA class ( p = 0.07 vs. baseline) persisted. Conclusions Applied resistance quadriceps training is safe in patients with CHF. It increases muscle strength, improves clinical status, exercise capacity, and quality of life.

Use of Anterior Tibial Translation in the Management of Patellofemoral Pain Syndrome in Older Patients: A Case Series

The currently most plausible pathophysiologic theory for the etiology of pain in patients with patellofemoral pain syndrome involves abnormal mechanical stress to the patellofemoral joint. At this time, there is no consensus nor is there a sufficient body of research evidence to guide management of patients with patellofemoral pain syndrome. This means that clinicians have to rely to some extent on a mechanism-based approach. Decreased quadriceps flexibility and muscular endurance have been identified as possibly relevant impairments in patients with patellofemoral pain syndrome. Surgical anterior translation of the tibial tuberosity with the Maquet procedure has a proven positive effect on patellofemoral contact forces. This case series studied the effects of a physical therapy management approach that included translating the tibia anteriorly while performing open kinetic chain quadriceps training and manual muscle stretching of the rectus femoris muscle. Outcome measures used included the numeric pain rating scale and goniometric measurement of rectus femoris muscle length in a standardized test position. Anterior tibial translation reduced pain during both interventions and also produced clinically and statistically significant pre- to post-intervention improvements in pain during manual muscle testing and rectus femoris length testing in addition to statistically significant pre- to post-intervention increases in rectus femoris muscle length. The results of this quasi-experimental study indicate the need for future experimental study. Future study should include functional in addition to impairment-based outcome measures, standardization and blinding for the rectus femoris muscle length test (should future researchers chose to again use this outcome measure), a pilot study establishing reliability of outcome measures collected by the therapist, younger subjects, and the collection of longer-term outcome data.

Superior Results With Eccentric Compared to Concentric Quadriceps Training in Patients With Jumper's Knee: A Prospective Randomised Study

Superior Results With Eccentric Compared to Concentric Quadriceps Training in Patients With Jumper's Knee: A Prospective Randomised Study

Superior results with eccentric compared to concentric quadriceps training in patients with jumper’s knee: a prospective randomised study

Background: A recent study reported promising clinical results using eccentric quadriceps training on a decline board to treat jumper’s knee (patellar tendinosis).Methods: In this prospective study, athletes (mean age 25...

Passive and dynamic translation in the knee is not influenced by knee exercises in healthy individuals

No evidence exists that repeated isolated quadriceps contractions lead to increased sagittal plane tibial translation. The purpose was to analyze passive and dynamic tibial translation before, during and after a specific exercise session, including cycling and a maximum number of knee extensions and heel-raises, in healthy individuals. Passive and dynamic sagittal tibial translation was measured on 18 healthy individuals (nine men and nine women) before, during and after a specific exercise session with heavy load, including cycling and maximum number of knee extensions and heel-raises. Sagittal tibial translation during the Lachman test, maximal isometric quadriceps contraction, one-legged squat and gait was registered with the CA-4000 electrogoniometer. The electromyographic (EMG) activity of m. vastus medialis and lateralis, m. gastrocnemius and mm. hamstrings was registered. There was no difference in passive or dynamic sagittal tibial translation during or after the exercise session. No difference could be detected in EMG activity during squat after compared with before the exercise session. In conclusion, the knee exercises did not influence the amount of translation in healthy individuals. The findings indicate that isolated strength training of quadriceps may be included in anterior cruciate ligament rehabilitation programs, even if further specific studies on injured individuals most be performed.

The effects of progressive resistance training for children with cerebral palsy

To investigate the effects of progressive resistance training of quadriceps and hamstrings muscles in children with cerebral palsy (CP). Pilot study using a repeated measures design with measurements at baseline, immediately after six weeks training then at four-week follow-up. The project was undertaken within the physiotherapy department of two special schools in Glasgow. A convenience sample of eight children aged between six and 12 years, with hypertonic CP. The subjects participated three times per week in a six-week, progressive, free-weight, strengthening programme. Maximum isometric muscle strength and resistance to passive stretch were measured with a hand-held myometer. The Gross Motor Function Measure and a 10-metre timed walking test, were used to assess function and gait parameters respectively. Muscle strength increased, with the quadriceps to hamstrings strength ratio moving towards normal. These changes were retained at follow-up. Muscle tone decreased and continued to decrease to follow-up. The standing (D) and walking, running and jumping (E) goal areas of the Gross Motor Function Measure showed improvement that continued towards follow-up. Walking speed and step rate increased. A future large-scale randomized controlled study would be of value to substantiate these results as the small convenience sample and lack of control group limit this study. However, the finding that no adverse effect accompanied the positive outcomes in strength and function may encourage clinicians to consider resistance training alongside standard therapeutic interventions.

Cerebral autoregulation is temporarily disturbed in the early recovery phase after dynamic resistance exercise

To determine cerebral blood-flow velocity (CBFV) and parameters of dynamic cerebral autoregulation (CA) during and after exhausting resistance exercise. Strength endurance (23 repetitions) and maximal strength training (8 repetitions) in 16 female and 16 male athletes on a leg curler (m. quadriceps training; approx. 2 s contraction) in the upright position. Registration of ECG, blood pressure by Finapres, CBFV by transcranial Doppler (TCD), and breathing by a Zak breathing-belt. Additional repetitive ergospirometry (O2-uptake, CO2-elimination, ventilation) and blood gas analyses were performed in a subgroup of seven athletes. From BP and CBFV cerebrovascular resistance (CVR), pulsatility index (PI) as well as LF-power, gain and phase-angle (frequency analysis) were derived. All athletes showed significant (p<0.01) 15 % to 30 % increases in CBFV during both training sets without signs of flow depression due to Valsalva maneuvers. In the early recovery, when blood pressure rapidly decreased, CBFV amplitude significantly (p<0.01) increased for 60-80 seconds with mean flow (Vm) at the exercise level, while CVR and PI showed conflicting results, similar to a presyncopal reaction. Ergospirometry and blood gas analyses revealed no evidence of major changes in pCO2, but phase angle was reduced (p<0.001) after exercise, together with an LF power increase (p<0.001). An unexpected increase in CBFV amplitude and in Vm occurs directly after dynamic resistance exercise without increased pCO2, which is comparable to a maximum leg press with hypercapnia. CVR and PI results as well as data from frequency analysis show similarities to presyncopal reactions, on the one hand, and point towards a temporarily disturbed cerebral autoregulation, on the other.

A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy

Objectives: This non-randomised pilot study investigated the effect of eccentric quadriceps training on 17 patients (22 tendons) with painful chronic patellar tendinopathy. Methods: Two different eccentric exercise regimens were used...

Pharmacotherapy for patellofemoral pain syndrome.

Patellofemoral pain syndrome (PFPS) is common among adolescents and young adults. It is characterised by pain behind or around the patella and crepitations, provoked by ascending or descending stairs, squatting, prolonged sitting with flexed knees, running and cycling. The symptoms impede function in daily activities or sports. Pharmacological treatments focus on reducing pain symptoms (non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticosteroids), or restoring the assumed underlying pathology (compounds containing glucosamine to stimulate cartilage metabolism, anabolic steroids to increase bone density of the patella and build up supporting muscles). In studies, drugs are usually applied in addition to exercises aimed at building up supporting musculature. This review aims to summarise the evidence of effectiveness of pharmacotherapy in reducing anterior knee pain and improving knee function in people with PFPS. We searched the Cochrane Musculoskeletal Injuries Group and Cochrane Rehabilitation and Related Therapies Field trials registers, the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2003), PEDro (up to January 2004), MEDLINE (1966 to January 2004), EMBASE (1988 to January 2004), and CINAHL (1982 to January 2004). Controlled trials (randomised or not) comparing pharmacotherapy with placebo, different types of pharmacotherapy, or pharmacotherapy to other therapies for people with PFPS. The literature search yielded 780 publications. Eight trials were included, of which three were of high quality. Data were analysed qualitatively using best evidence synthesis, because meta-analysis was impeded by differences in route of administration of drugs, care programs and outcome measures. Four trials (163 participants) studied the effect of NSAIDs. Aspirin compared to placebo in a high quality trial produced no significant differences in clinical symptoms and signs. Naproxen produced significant short term pain reduction when compared to placebo, but not when compared to diflunisal. Laser therapy to stimulate blood flow in tender areas led to more satisfied participants than tenoxicam, though not significantly. Two high quality RCTs (84 participants) studied the effect of glycosaminoglycan polysulphate (GAGPS). Twelve intramuscular injections in six weeks led to significantly more participants with a good overall therapeutic effect after one year, and to significantly better pain reduction during one of two activities. Five weekly intra-articular injections of GAGPS and lidocaine were compared with intra-articular injections of saline and lidocaine or no injections, all with concurrent quadriceps training. Injected participants showed better function after six weeks, though only the difference between GAGPS injected participants and non-injected participants was significant. The differences had disappeared after one year. One trial (43 participants) found that intramuscular injections of the anabolic steroid nandrolone phenylpropionate significantly improved both pain and function compared to placebo injections. There is only limited evidence for the effectiveness of NSAIDs for short term pain reduction in PFPS. The evidence for the effect of glycosaminoglycan polysulphate is conflicting and merits further investigation. The anabolic steroid nandrolone may be effective, but is too controversial for treatment of PFPS.

Strength and Flexibility of the Quadriceps Muscle in Adolescent Athletes with Osgood-Schlatter Disease.

In order to investigate the prevention of Osgood-Schlatter disease (OSD) in adolescent athletes, the strength and flexibility of the quadriceps muscles were examined in 30 adolescent athletes with unilateral OSD and 20 adolescent soccer players as a control. The following three factors were examined: 1) quadriceps strength in concentric and eccentric contraction, 2) quadriceps flexibility, and 3) the laterality of the involved knee. There was no significant difference in quadriceps muscle strength between athletes with OSD and soccer players, while quadriceps muscle flexibility in athletes with OSD was significantly low in comparison with soccer players. Although there was no significant difference in quadriceps muscle strength between the uninvolved and involved sides in our patients with unilateral OSD, the left knee was more prone to be affected than the right knee in adolescent athletes. In the great majority of adolescent athletes, the left knee had a tendency to be a dominant leg which was defined as the take-off leg. Since the dominant leg is susceptible to eccentric quadriceps contraction during rapid deceleration while jumping, landing or running when playing sport, we consider that these factors may play a role in the decrease of the quadriceps muscle flexibility in adolescent athletes with OSD. With regard to the prevention of OSD, stretching exercises to relieve the decrease of the quadriceps muscle flexibility and training to reduce the load on the dominant leg are recommended in adolescent athletes.

Strength and function before and after anterior cruciate ligament reconstruction.

Rehabilitation of patients with anterior cruciate ligament injury is a topic of interest among clinicians. Although numerous studies report the deficits after anterior cruciate ligament reconstruction, there are no data available on the changes in strength and functional performance before and 6 months after reconstruction surgery. This is when most patients are returning to sports activities. In the current study 31 patients with complete unilateral anterior cruciate ligament ruptures followed a controlled rehabilitation program emphasizing early range of motion after surgery and quadriceps strengthening before and after undergoing bone-patellar tendon-bone reconstruction. Strength of the hamstrings and quadriceps and five functional activities were assessed at 1 week before and 6 months after surgery. Preoperative strength assessments using a Cybex II dynamometer showed a 12% quadriceps deficit at 60 degrees per second and 9% deficit at 120 degrees per second with no hamstring deficit in the injured leg compared with the uninjured leg. Despite intensive quadriceps training, the postoperative quadriceps deficit increased to 28% at 60 degrees per second and 22% at 120 degrees per second in comparison with the uninjured leg. There was no change in hamstring strength in the injured leg. Most functional measures improved after surgery. The shuttle run improved by 10%, the side step test results improved by 17%, and the carioca test results improved by 23%. No significant difference was found in the results of the hop test. This study highlights the extent of the quadriceps deficits despite functional improvement and the difficulty in restoring quadriceps strength after bone-patellar tendon-bone reconstruction. It also questions the relationship of current functional tests to quadriceps strength and the role of maximum strength testing as a predictor of function and of safe sporting performance.

The Q angle and sport.

Quadriceps muscle contraction tends to straighten the Q angle. We expected that sports comprising a high amount of quadriceps training could be associated with low Q angles. The aim of the present study was to estimate the Q angle in athletes and to investigate its potential associations with participation in sport. Three hundred and thirty-nine athletes had their Q angle measured. The mean of right-side Q angles was higher than left side, and the mean Q angle was higher in women than in men. The Q angle was positively associated with years of jogging, and negatively with years of soccer, swimming and sports participation at all. It is concluded that the use of Q angle measurements is questionable.

Resilience to Exercise Detraining in Healthy Older Adults

To determine the effects of stopping and restarting two types of exercise programs in older adults. A controlled, longitudinal study that utilized random assignment of volunteers. Treatments were exercise programs designed to improve cardiovascular or neuromuscular fitness. Dependent variables measured before and after implementation of treatments were: maximum oxygen consumption, oxygen pulse, treadmill and cycle training workloads, quadriceps isokinetic peak torque, quadriceps isokinetic total work, and quadriceps training workload. Exercise training was highly effective in improving cardiovascular endurance or muscular strength. Ten weeks of exercise detraining resulted in small losses in newly gained cardiovascular capacity but more noticeable losses in muscular strength. Exercise retraining was accomplished easily using cardiovascular or resistive exercises. The functional benefits of restarting a cardiovascular exercise program appeared additive despite a 10-week intervening period of exercise detraining. In this age group, cardiovascular exercise produced limited improvements in muscular strength, and resistive exercise training positively influenced cardiovascular exercise performance. Older adults are fairly resilient to 10 weeks of cardiovascular detraining and retain newly gained muscular strength for at least 5 weeks, despite an interruption of formal exercise. An occasional missed exercise session or temporary cessation of habitual exercise should not be a cause for distress in exercising older adults. Instead, they should realize the case with which they may restart their exercise program and also appreciate the generalized fitness benefits that can be ascribed to becoming more active.

Knee extension strength and walking speed in relation to quadriceps muscle composition and training in elderly women

Knee extension strength, walking speed, quadriceps muscle mass and composition of the muscle compartment were studied in 66 to 85-year-old female athletes and controls. Maximal voluntary knee extension force, force/body mass, extension torque, torque/body mass and walking speed were higher for the athletes than the controls. A muscle index indicating intramuscular fat and connective tissue measured using ultrasonography was lower for the athletes than the controls. There were no differences between the study groups in knee extension force related either to cross-sectional area (CSA) or lean tissue area (CSAL) of the quadriceps. Within the subgroups, there was no significant correlation between knee extension torque and CSA or CSAL of the same muscle. In the athletes high knee extension torque/body mass was related to a low muscle index and high walking speed to a low relative proportion of fat in the muscle. The muscle index was lower the more kilometers trained during the preceding year. In the controls high knee extension torque/body mass and high walking speed were related to a low relative proportion of fat. Knee extension torque and walking speed were higher the more kilometers walked during the preceding year. The results indicate that elderly female athletes have superior muscle performance compared to their age-peers. Performance in a maximal isometric strength test in elderly women is not clearly related to muscle mass. However, to some extent it is related to the composition of the same muscle, especially the degree to which fat is infiltrated into the muscle.

Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps.

Four male subjects aged 23-34 years were studied during 60 days of unilateral strength training and 40 days of detraining. Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular velocity of 2.09 rad.s-1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length (Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at 30 degrees before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad.s-1. After 60 days T leg CSA had increased by 8.5% +/- 1.4% (mean +/- SEM, n = 4, p less than 0.001), iEMG by 42.4% +/- 16.5% (p less than 0.01) and MVC by 20.8% +/- 5.4% (p less than 0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while iEMG and MVC increased by 24.8% +/- 10% (N.S.) and 8.7% +/- 4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal at 2/10 Lf (12.0% +/- 1.5%, p less than 0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5% +/- 1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus femoris and lateralis muscles was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Knee effusion and reflex inhibition of the quadriceps. A bar to effective retraining.

In order to investigate the difficulty of quadriceps training in the presence of an effusion into the knee we examined 13 patients with chronic effusions by recording isometric muscle strength. Maximal strength was markedly lower in the presence of an effusion, and aspiration of the effusion produced a 13.6% increase in strength (p less than 0.01). A further, small increase of 8% was recorded after intra-articular lignocaine injection. Isometric strength and surface integrated EMG correlated well in six patients. Two reflex mechanisms seem to inhibit quadriceps innervation in the presence of a persistent knee effusion, one mediated by pressure sensitive receptors, the other still unknown. Joint aspiration and systemic or intra-articular anti-inflammatory drug treatments are advised before any programme of quadriceps training to allow maximum effects to be achieved.

Quadriceps function and training after knee ligament surgery

A follow-up study of 30 patients operated on for knee ligament injuries was performed with measurements of maximal isometric and isokinetic (angular velocity 30, 42, 120 degrees/s) torque for knee extension and muscle biopsy from vastus laternalis. The maximal torque values of the operated side were reduced in spite of resumed physical activities and athletic training. Isokinetic training, weight training (10 RM), and self-training were compared. All training groups increased their muscle strength with the largest increase for the isokinetically trained group. Before training, the mean fiber areas were somewhat low, especially for type II fibers and there was a tendency for an increase after training. There was no significant change in ATP, CP, and contractile enzyme activities with training. With the isokinetic training principle, maximal torque can in contrast to weight training be achieved through the whole range of motion, which may explain its larger training effect.