Isometric Quadriceps Strength Research Articles

Relationship between Exercise Tolerance and Respiratory Pattern and Muscular Strength of Legs in Patients with Chronic Heart Failure.

The main symptom of chronic heart failure (CHF) is dyspnea and leg fatigue on exercise, demonstrating a decrease in exercise capacity. However, the precise mechanisms of these symptoms are not fully understood. The existence of a relationship between exercise tolerance and respiratory pattern and muscular strength of legs in patients with CHF has not been demonstrated. In this study, therefore, we measured these parameters to clarify the factors which relate to exercise tolerance in CHF patients. Subjects were fifty-four consecutive patients (37 men and 17 women, mean age 53 years) with CHF who underwent cardiopulmonary exercise testing at our hospital from February 1999 to September 2000. Peak oxygen uptake (peak VO2) and respiratory pattern (TV/RR; tidal volume/respiratory rate) were evaluated. The strength of quadriceps was also measured. The respiratory pattern was weak but significantly correlated with peak VO2 (r=0.27, p<0.05). Maximal isometric strength of quadriceps showed a tendency to correlate with peak VO2 (r=0.25, p=0.06). These findings suggest that exercise intolerance, seen in these CHF patients, is related to both respiratory pattern and the maximal muscular strength of legs.

Tests for physical function of the elderly with knee and hip osteoarthritis.

This study reports the results of a battery of physical function tests used to assess physical function of older patients with clinical knee and/or hip osteoarthritis (OA), and the correlation to the WOMAC Index (disease-specific questionnaire). A total of 106 sedentary subjects, aged >60 years (mean 69.4, S.D. 5.9) with hip and/or knee OA (mean 12.2 yrs, S.D. 11.0) participated in the study. Mobility, joint flexibility and muscle strength were evaluated by recording time to: walk a distance of 8', ascend/descend 4 stairs, rise from/sit down from a chair (5 times). Hip/knee flexion and isometric quadriceps strength were also measured. Categories of performance were formed by dividing data into quartiles for each test (1=highest, 4=lowest score, 5=unable to complete) and, by summing the category scores, a total summary score (TSS) was obtained. The battery of physical function tests showed an acceptable test-retest reliability (ICC of all tasks > or =0.80) and internal consistency (Cronbach's alpha > or =0.80). Performance scores on walking, stair climb, chair-rise and ROM of affected OA joints were significantly correlated with each other, and with the WOMAC Index (P<0.05, Spearman's correlation). Lower scores on the TSS were associated with lower scores on all the WOMAC Index items (P<0.001). This study shows that a simple battery of physical function tests in combination with the WOMAC Index are reliable and may be useful outcome measures in the evaluation of therapeutic interventions and geriatric rehabilitation.

The Long-term Effects of Unilateral Lower Limb Musculoskeletal Injury on Bone Mineral Density and Isometric Quadriceps Strength

Summary Musculoskeletal injuries of the lower limb are commonplace and can lead to long-standing deficits in bone mineral density (BMD) and muscle strength. This may predispose subjects to re-injury and lower their threshold for functional ability. This study aims to investigate the relationship between BMD and peak isometric quadriceps strength and considers whether subsequent strength training is of benefit. Ten subjects (two female) with previous lower limb musculoskeletal injuries were assessed. The BMD in the knee region was measured bilaterally using dual energy X-ray absorptometry (DEXA, model DPX-L). The peak isometric quadriceps strength was assessed using the KinCom 500H isokinetic dynamometer. The injured limb was compared to the uninjured limb (I/UI%). Significant differences were seen between the injured and uninjured limb for BMD in the femur (p = 0.039), tibia (p = 0.014) and in the combined site (p = 0.017); and peak isometric quadriceps strength (p > 0.001). No relationship was found between the decrements in muscle strength and BMD. A further pilot study (n = 6) was conducted to assess the impact of a 12-week home exercise training programme on the BMD and isometric quadriceps strength deficits. These results were encouraging with increases in the quadriceps strength and/or BMD and a statistically significant increase in the load lifted in training.

A mechanism for increased contractile strength of human pennate muscle in response to strength training: changes in muscle architecture.

1. In human pennate muscle, changes in anatomical cross-sectional area (CSA) or volume caused by training or inactivity may not necessarily reflect the change in physiological CSA, and thereby in maximal contractile force, since a simultaneous change in muscle fibre pennation angle could also occur. 2. Eleven male subjects undertook 14 weeks of heavy-resistance strength training of the lower limb muscles. Before and after training anatomical CSA and volume of the human quadriceps femoris muscle were assessed by use of magnetic resonance imaging (MRI), muscle fibre pennation angle (theta(p)) was measured in the vastus lateralis (VL) by use of ultrasonography, and muscle fibre CSA (CSA(fibre)) was obtained by needle biopsy sampling in VL. 3. Anatomical muscle CSA and volume increased with training from 77.5 +/- 3.0 to 85.0 +/- 2.7 cm(2) and 1676 +/- 63 to 1841 +/- 57 cm(3), respectively (+/- S.E.M.). Furthermore, VL pennation angle increased from 8.0 +/- 0.4 to 10.7 +/- 0.6 deg and CSA(fibre) increased from 3754 +/- 271 to 4238 +/- 202 microm (2). Isometric quadriceps strength increased from 282.6 +/- 11.7 to 327.0 +/- 12.4 N m. 4. A positive relationship was observed between theta(p) and quadriceps volume prior to training (r = 0.622). Multifactor regression analysis revealed a stronger relationship when theta(p) and CSA(fibre) were combined (R = 0.728). Post-training increases in CSA(fibre) were related to the increase in quadriceps volume (r = 0.749). 5. Myosin heavy chain (MHC) isoform distribution (type I and II) remained unaltered with training. 6. VL muscle fibre pennation angle was observed to increase in response to resistance training. This allowed single muscle fibre CSA and maximal contractile strength to increase more (+16 %) than anatomical muscle CSA and volume (+10 %). 7. Collectively, the present data suggest that the morphology, architecture and contractile capacity of human pennate muscle are interrelated, in vivo. This interaction seems to include the specific adaptation responses evoked by intensive resistance training.

Physiotherapy for anterior knee pain: a randomized controlled trial. (City Hospital Nottingham, Nottingham, United Kingdom) Ann Rheum Dis 2000;59:700-704.

This observer blind, prospective, factorial design randomized controlled trial determined the efficacy of the individual components of physiotherapy in subjects with anterior knee pain. Eighty-one young adults with anterior knee pain were randomly allocated to one of four treatment groups: (1) exercise, tapping, and education; (2) exercise and education; (3) taping and education; and (4) education alone. Each group received 6 physiotherapist-led treatments over 3 months. Follow up took place at 3 months using the following outcomes measures: Patient satisfaction; a visual analogue pain score; the WOMAC lower limb function score; the Hospital Anxiety and Depression scale (HAD); and quadriceps strength. At 12 months the WOMAC and HAD were assessed by postal questionnaire. All groups showed significant improvements in WOMAC, visual analogue, and HAD scores; these improvements did not vary significantly between the four groups or between exercising/nonexercising and taped/nontaped patients at 3 and 12 months. However, patients who exercised were significantly more likely to be discharged at 3 months than nonexercising patients. Taping was not significantly associated with discharge. Significantly greater improvements in WOMAC, visual analogue, and the anxiety score were seen in patients who were discharged than in those who were referred. Conclude the proprioceptive muscle stretching and strengthening aspects of physiotherapy have a beneficial effect at 3 months sufficient to permit discharge from physiotherapy. These benefits are maintained at 1 year. Taping does not influence the outcome. Comment by Phillip S. Sizer Jr., MEd, P.T. The investigators evaluated a total of 81 patients (36 female and 45 male) between the ages of 16 and 40 years with a history of anterior knee pain of more than three months. Patients were evaluated through history, locomotor examination, WOMAC score and Hospital Anxiety and Depression scale (HAD). In addition, isometric quadriceps strength and power were measured before and after treatment. Patients were randomly assigned to one of four different groups: (1) exercise, taping, and education; (2) taping and education; (3) exercise and education; and (4) education alone. Each patient received six treatments over a three-month period. Through a 2 × 2 factorial analysis design, the investigators discovered that the group participating in exercise were significantly more likely to be discharged than non-participants. Additionally, they found that taping alone was not significantly associated with discharge. Furthermore, they observed no difference between groups for the WOMAC score and the visual analogue pain score. Finally, they found that education alone resulted in the sufficient improvement of 60% of those subjects without need for other intervention, supporting the value of therapist contact and simple advice. These investigators embarked upon the evaluation of a controversial condition whose etiology is not well understood.1 Recent investigators have revealed alternative explanations for persistent anterior knee pain, including increased patelo-femoral joint stress2,3 and receptor neuro-sensitization within the lateral retinaculum.4 These outcomes may reflect the influence of exercise on those factors and support the use of physical therapy in the treatment of anterior knee pain.

Myosin heavy chain IIX overshoot in human skeletal muscle

The distribution of myosin heavy chain (MHC) isoforms, fiber type composition, and fiber size of the vastus lateralis muscle were analyzed by sodium dodecylsulfate polymerase gel electrophoresis (SDS-PAGE), ATPase histochemistry, and immunocytochemistry in a group of adult sedentary men before and after 3 months of heavy-load resistance training and, subsequently, after 3 months of detraining. Following the period of resistance training, MHC IIX content decreased from 9.3 ± 2.1% to 2.0 ± 0.8% (P < 0.01), with a corresponding increase in MHC IIA (42.4 ± 3.9% vs. 49.6 ± 4.0% [P < 0.05]). Following detraining the amount of MHC IIX reached values that were higher than before and after resistance training (17.2 ± 3.2% [P < 0.01]). Changes in fiber type composition resembled the changes observed in MHC isoform content. Significant hypertrophy was observed for the type II fibers after resistance training. Maximal isometric quadriceps strength increased after resistance training, but returned to pretraining levels after detraining. The present results suggest that heavy-load resistance training decreases the amount of MHC IIX while reciprocally increasing MHC IIA content. Furthermore, detraining following heavy-load resistance training seems to evoke an overshoot in the amount of MHC IIX to values markedly higher than those observed prior to resistance training. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 1095–1104, 2000

Osteoarthritis of the knee: Isokinetic quadriceps exercise versus an educational intervention

Objective: To evaluate the effects of isokinetic exercise versus a program of patient education on pain and function in older persons with knee osteoarthritis. Design: A randomized, comparative clinical trial, with interventions lasting 8 weeks and evaluations of 12 weeks. Setting: An outpatient Veterans Affairs Medical Center clinic and an affiliated university hospital. Patients: One hundred thirteen men and women between 50 and 80 years old with diagnosed osteoarthritis of the knee; 98 completed the entire assigned treatment. Intervention: Patients received either a regimen of isokinetic exercise of the quadriceps muscle three times weekly over 8 weeks or a series of 4 discussions and lectures led by health care professionals. Main Outcome Measures: Variables studied for change were isokinetic and isometric quadriceps strength, pain and function determined by categorical and visual analog scales, and overall status using physician and patient global evaluations by the Arthritis Impact Scale, version 2, Western Ontario McMaster's Arthritis Index, and Medical Outcome Study Short Form 36. Results: Both treatment groups showed significant strength gains ( p < .05), which occurred over a wider velocity spectrum for the exercise group. Exercised patients also had improved pain scores for more of the variables measured than those receiving education. Both groups had positive functional outcomes and slightly improved measures of overall status. Conclusions: Isokinetic exercise is an effective and well-tolerated treatment for knee osteoarthritis, but a much less costly education program also showed some benefits.

Quadriceps inhibition following arthroscopy in patients with anterior knee pain

Objectives. This study was aimed at investigating muscle strength and quadriceps inhibition in patients with unilateral anterior knee pain syndrome. Design. Functional assessments were made before an arthroscopic knee surgery and 6 weeks and 6 months following the surgical intervention. Background. Traumatic knee injuries have been associated with severe muscle inhibition of the knee extensor muscles. Muscle inhibition is a serious hindrance in the rehabilitation process and prevents full functional recovery of the affected joint. Methods. 30 patients participated in the study. Isometric quadriceps strength was measured using a KinCom dynamometer. Muscle inhibition was assessed using the interpolated twitch technique which requires applying a single electrical twitch to the femoral nerve during a maximal isometric knee extensor contraction. Pain was assessed with a 100 mm visual analogue pain scale. Results. Pre-surgery, substantial muscle inhibition and pain was observed in the affected leg compared with the contralateral leg. Over the 6 month period there was a decrease in pain and muscle inhibition, although the decrease in muscle inhibition failed to reach statistical significance. Muscle strength showed a decrease 6 weeks post-surgery followed by an increase 6 months following surgery compared with pre-surgical values. Conclusions. The arthroscopic intervention was successful in reducing pain in patients with unilateral anterior knee pain syndrome. However, muscle inhibition was still substantial 6 months following surgery and was significantly higher in the affected and contralateral limb than in normal subjects.

THE EFFECT OF TWO REHABILITATION PROGRAMS ON ISOMETRIC QUADRICEPS STRENGTH IN PATELLOFEMORAL PAIN PATIENTS

1712 Patients diagnosed with Patellofemoral Pain Syndrome (PFPS) most commonly undergo a conservative treatment protocol. The aim of this study was to determine if there was a difference in the effect of a course of physical therapy versus a home exercise program on isometric quadriceps strength over a 42 day interval. Thirty-five subjects, with no history of knee disorders that were diagnosed with PFPS, were randomly assigned into a standard physical therapy program or a standard home exercise program. Eight females and seven males (mean age 27.1 ± 4.8) underwent a course of physical therapy twice a week for approximately forty minutes per session. Eight females and eight males (mean age 26.2 ± 2.3) underwent a structured home exercise program recommended at five times per week at twenty minutes per session and were monitored by an exercise log. Seventeen non-pathological subjects served as controls (mean age 25.6 ± 1.8). The force exerted by the quadriceps at a 30 ° angle of knee flexion during three maximal voluntary isometric contractions (MVICs) was evaluated at entrance into each program and at completion of each program using the Kincom 125 AP (Chattanouga, Tennessee). The mean increase in maximal force from day 1 to day 42 of the home exercise group was 14.73% and in the physical therapy group it was 22.42%. The mean increase in the control population was 0.25%. The intergroup difference was significant (p=.0014). This study suggests that both rehabilitative programs were effective for gains in force exerted by the quadriceps. However, the physical therapy program showed a greater increase in force over the study's duration.

Effects of detraining on knee extensor strength and functional mobility in a group of elderly women.

Long-term detraining results for individuals 75 years and older are needed. The purpose of this study was to assess long-term detraining effects on quadriceps strength and functional mobility in nursing home residents. Ten women (X = 82.8 years) who completed a strength training program were reassessed 1 year later. Clinical methods were used to remeasure dynamic and isometric quadriceps strength and functional mobility. One repetition maximum quadriceps strength declined 68.3% (p < 0.05) from trained values. Isometric strength losses were 29.8% at 90 degrees (p < 0.05), 28.7% at 60 degrees (p < 0.05), and 24.4% at 20 degrees (p < 0.05) of knee flexion 1 year postexercise. Fast-paced walking, self-selected paced walking, and timed up and go speed decreased 28.6% (p < 0.05), 19.5% (p < 0.05), and 54.1% (not significant), respectively, from posttraining. One year vs. baseline, isometric strength decreased 0-14.3%, dynamic strength decreased 48.9%, and functional mobility declined 16.5-20.7% despite an intervening training program. An increased strength loss rate beyond the age of 80 years may be a major factor influencing functional independence.

Determinants of age-associated changes in os calcis ultrasonic indices in elderly women: potential involvement of geriatric hyposomatotropism in bone fragility.

ultrasound measures a clinically relevant property of bone strength in addition to and distinct from bone mass. The aim of the present study was to examine the effects of healthy ageing on ultrasound measurements of the calcaneus. cross-sectional study. a sample of 177 community-dwelling healthy women aged 70-87 years. Exclusion criteria were diseases or medications known to affect the musculoskeletal system or the somatotrophic axis. serum levels of 1,25-dihydroxyvitamin D3 and insulin-like growth factor-I (IGF-I) were measured by radioimmunoassay, serum 25-hydroxyvitamin D3 (25(OH)D3) was determined by competitive binding assay and serum parathyroid hormone was assessed immunochemically. Isometric and isokinetic quadriceps strength were evaluated using a Cybex II system. Calcaneal ultrasound indices--broadband ultrasound attenuation (BUA) and speed of sound (SOS)--were measured with an Achilles system. we found a significant decrease with ageing in BUA and SOS (-0.5 and -1.3% per year, respectively), suggesting a continuing loss of bone quality. Quadriceps strength, serum IGF-I and 25(OH)D3 constituted the best predictors of BUA, while IGF-I was the only parameter found to be independently associated with SOS. these findings suggest that, among other factors, the activity of the growth hormone-IGF-I axis is of importance for skeletal integrity. Age-related bone fragility may, in part, be related to geriatric hyposomatotropism.

Hip bone mineral density is improved by high-impact aerobic exercise in postmenopausal women and men over 50 years.

Fifteen men and women (six men) between the ages of 50 and 73 years were recruited to begin keep-fit classes. They were matched for sex, age, menopausal status and mass to 15 non-exercising controls. The keep-fit classes were two to three times a week and included high-impact exercise, including step and jumping exercises specifically to load the proximal femur and spine. Proximal femur, lumbar spine and total body bone mineral density (BMD) were measured at 0 and 12 months. Urinary pyridinoline (Pyr) and deoxypyridinoline (dPyr) crosslinks were measured every 6 months to assess bone resorption. Quadriceps isometric strength was measured every 6 months. BMD increased non-significantly at the femoral neck [1.57 (0.8)%] and Wards triangle [1.97 (1.4)%], and significantly at the greater trochanter 2.21 (0.9)% (P = 0.02) in the exercise group. Femoral neck BMD decreased by -1.9(0.8)% (P = 0.049) in the control group, which was significantly different from the change in the exercise group (P = 0.009). BMD did not change at the Wards triangle or trochanter in the controls. Lumbar spine BMD did not change in either group. Total body BMD did not change in the exercise group, but decreased by -0.79 (0.3)% (P = 0.02) in the controls. Following 6 months of the exercise classes. Pyr and dPyr crosslinks were significantly reduced [-19.0 (7.2)%; P = 0.0019 and -20.0 (7.7)%; P = 0.021 respectively]. There was no significant change in crosslinks after 1 year, and no change at any time in the controls. Quadriceps strength changed by 5.4 (3.7)% in the exercise group and by -6.9 (2.5)% (P = 0.01) in the control group after 12 months, being significant between groups (P = 0.008). This study suggests that high-impact, aerobic exercise in postmenopausal women and men over 50 years old is feasible and effective at maintaining muscle strength and increasing proximal femur BMD but not spine or total body BMD.

Relationship between baseline insulin-like growth factor-I (IGF-I) and femoral bone density in women aged over 70 years: potential implications for the prevention of age-related bone loss.

To test the hypothesis that the decline in femoral bone mass associated with healthy aging is partially accounted for by deficiency of the growth hormone-insulin-like growth factor-I (IGF-I) axis. Cross-sectional study. A sample of 245 community-dwelling healthy women aged 70 and older. Exclusion criteria were diseases or medications known to affect the musculoskeletal system or the somatotrophic axis. Serum levels of IGF-I, calcitriol, and osteocalcin were determined by radioimmunoassay; serum calcidiol was measured by competitive binding assay, and serum parathyroid hormone (PTH) was assessed immunochemically. Urinary pyridinium crosslinks were measured by fluorescent detection after high-pressure liquid chromatography. Isometric and isokinetic quadriceps strength was evaluated using an isokinetic dynamometer. Bone density (BMD) was assessed by dual-energy X-ray absorptiometry at the proximal femur. Multiple regression was used to adjust for potential confounders. At the proximal femur, BMD declined by 0.59-0.84% per year. In addition to body mass index and muscle strength, serum IGF-I was found to be an independent predictor of BMD at all femoral sites. The data support the hypothesis that circulating IGF-I not only reflects the integrated growth hormone secretion but also has a direct role in the endocrine regulation of bone remodeling. The present findings support the need for further studies to assess the potential of IGF-I in attenuating age-related femoral bone loss.

The Influence of Aging on Muscle Strength and Muscle Fiber Characteristics With Special Reference to Eccentric Strength

It is well established that aging seriously reduces isometric and concentric muscle strength due to atrophy, deterioration of mechanical properties, and motor unit loss. However, there is limited information on the impact of aging on eccentric strength despite the fact that such forces play an equally important role during daily activities. The purpose of this study was to examine the influence of aging on three expressions of muscle strength (isometric, concentric, and eccentric) in relation to muscle fiber characteristics, with special emphasis on eccentric force. Sedentary but healthy men (age range 18-80 years, n = 60) and women (20-74 years, n = 30) were tested for maximal effort isometric, concentric, and eccentric (1.05, 2.09, 3.14 rads.s-1) quadriceps strength, body composition, and muscle fiber characteristics of the vastus lateralis (men only). There was a significant (p < .05) approximately 30 N per decade decline in isometric and concentric forces, but only 9 N per decade reduction in eccentric strength. There was a significant reduction in Type II muscle fiber area with aging (p < .05). Isometric, eccentric, and concentric force correlated r = .33, r = .32 (p < .05), and r = .12 (p > .05) with Type II muscle fiber area, respectively. The correlation between age and fat-free mass/force ratio ranged from r = .39 to .43 in men and r = .27 to .50 in women. The data suggest a relative preservation of eccentric strength with aging in men and women that seems to be independent of muscle mass or muscle fiber type or size.

Isometric and isokinetic quadriceps strength in gonarthrosis; Inter-relations between quadriceps strength, walking ability, radiology, subchondral bone density and pain

Patients with osteoarthrosis suffer from disability and pain. We measured isokinetic and isometric peak torque in 20 women with gonarthrosis (GA) and in 26 healthy controls. Relationships between muscle strength, walking and stair climbing time, pain level and pain disability scores as assessed by the patients using an extensive questionnaire, radiological changes and subchondral sclerosis expressed as bone mineral density (BMD, g/cm2) of the proximal tibia were studied. Precision errors of the torque measurements in both GA patients and controls were approximately 6%. In the GA patients, isokinetic and isometric quadriceps strength was reduced by 40 and 15% (p < 0.01) respectively, and walking and stair climbing time was increased by 30% (p < 0.005). Isokinetic strength was a better predictor of pain level and pain disability scores than isometric strength and radiological stage. Walking time and stair climbing time were not associated with quadriceps strength, pain level, pain disability scores or radiological changes. Subchondral BMD was not predictive of pain. The study suggests that quadriceps strength assessed by isokinetic dynamometry in GA is a reliable measurement. Isokinetic strength was pronouncedly reduced compared to isometric strength and was a more important predictor of pain and pain disability than isometric strength. These findings should be taken into consideration when planning exercise studies and programmes in GA.

The quadriceps strength of healthy elderly people remeasured after eight years

Isometric quadriceps strength was remeasured in 14 healthy survivors of a group of elderly people first studied 8 years previously. There were 4 men (median age 81 years, range 79 to 84) and 10 women (82 years, range 79 to 89). They were selected for their health, not their levels of physical activity. Nevertheless, they were active when first studied and, with 1 exception, had maintained or increased their levels of physical activity. Isometric quadriceps strength was well preserved; the median change in the strength of the stronger quadriceps was only -0.3% per annum (95% confidence interval = -1.4 to +0.8).

Human quadriceps strength and fatiguability in patients with post viral fatigue.

Quadriceps isometric strength, activation and fatiguability were measured in 11 patients with symptoms of fatigue three months after glandular fever or a glandular fever-like illness. Predicted normal and lower limits of normal muscle strength were calculated from height and age. These measures and the fatigue index were compared with a group of healthy students of similar age. Two of the patients were unable to activate fully their muscles. After allowing for this inhibition the group mean (SD) strength was 104 (22%) of predicted. Although there was no significant difference in the fatigue index between the patients and the control group, there was a trend for the patients to show less fatigue than controls. There was no difference in the muscle results for those patients who were found to have Epstein-Barr virus infections and those who did not. The feelings of weakness and fatigue experienced by the patients could not be explained by either physiological muscle fatigue or lack of effort.

Effects of ibuprofen on exercise-induced muscle soreness and indices of muscle damage.

Thirty-two volunteers participated in a two-period crossover study in which ibuprofen was tested against an identical placebo for its effectiveness in reducing muscle soreness and damage after two bouts of downhill running. Subjective soreness, quadriceps isometric strength and isometric endurance time at 50 percent of maximum strength, serum activities of creatine kinase, lactate dehydrogenase and aspartate transaminase and serum levels of creatinine and urea were recorded at intervals up to 72 hours after exercise. Each downhill run produced muscle soreness, and a decline in muscle strength and 50 percent endurance time, although these parameters were unaffected by ibuprofen treatment. All serum parameters measured increased after both runs, but for the three enzymes this increase was smaller after the second run. Serum creatine kinase and urea levels were higher in the ibuprofen group after both runs. These results indicate that ibuprofen is not an appropriate treatment for delayed onset muscle soreness and damage.

Muscle adaptations and glucose control after physical training in insulin-dependent diabetes mellitus.

Six men and three women with insulin-dependent diabetes (without complications) participated in physical training three times a week for 20 weeks. Physical training did not change the concentration of fasting blood-glucose, glucose excretion in urine or glucosylated haemoglobin (HbA1). However, the glucose disposal rate during euglycaemic clamp increased after training. In two patients a minor reduction of insulin dosage was necessary to alleviate slight hypoglycaemic episodes. The training resulted in significant increases in quadriceps isometric and dynamic strength and endurance. Maximal oxygen uptake increased by 8%, the activity of glycolytic enzymes in vastus lateralis muscle by 47% for hexokinase, and 30% for tri-osephosphate dehydrogenase and 25% for lactic dehydrogenase, the activity of oxidative enzymes by 42% for citrate synthase and 46% for 3-hydroxy-acyl-CoA-dehydrogenase. The glycogen concentration in the vastus lateralis muscle did not change significantly. Lipoprotein lipase activity did not change in muscle, nor in adipose tissue. The mean muscle fibre area increased by 25% and the area of FTa fibres by 30%. The new formation of capillaries around different muscle fibres was significant for FTb fibres (26%). The proliferation of capillaries, however, appeared to be insufficient to cope with the increased area of muscle fibres. As a result, the mean area of muscle fibre supplied by one capillary (a measure of diffusion distance) significantly increased after training for FTa fibres. It is concluded that with the exception of deficient proliferation of capillaries, patients with insulin-dependent diabetes mellitus show a normal central and peripheral adaptation to physical training. Physical training does not apparently improve blood glucose control in most cases, despite an increased insulin sensitivity.

The effects of electrical stimulation on the quadriceps during postoperative knee immobilization.

Immobilization of the knee after anterior cruciate ligament (ACL) reconstruction results in marked thigh atrophy and decrease in quadriceps strength that may prolong the rehabilitation program of the injured athlete. Fifteen male volunteers undergoing ACL reconstruction were divided into two groups, stimulation (during immobilization) and nonstimulation. Measurements of thigh circumference and isometric quadriceps strength were tested preoperatively, immediately after cessation of cast immobilization (6 weeks), and at 9 and 12 weeks postoperatively. The changes in circumference and strength between the first preoperative test and all subsequent tests were compared for statistical significance (Student's t-test, P less than 0.5) between the two groups. The decrease in quadriceps strength of the stimulation group during immobilization was significantly less than that of the nonstimulation group, although later differences between the two groups were not significant. There were no significant differences in thigh atrophy between the two groups. In conclusion, isometric quadriceps torque decreases resulting from immobilization can be significantly lessened by application of electrical stimulation during immobilization. Electrical stimulation to the quadriceps does not significantly alter thigh circumference changes that occur during immobilization.