Biomedical subjects

D R Sinacore

Publications and source records attributed to D R Sinacore.

At least 37 records · Page 2Linked to original sources

PubMed1994

Recovery from a 1-minute bout of fatiguing exercise: characteristics, reliability, and responsiveness.

BACKGROUND AND PURPOSE: The purposes of this study were (1) to describe the characteristics of recovery of peak torque after a 1-minute bout of isokinetic exercise of the quadriceps femoris muscle, (2) to determine the short-term reliability of the recovery of peak torque, and (3) to determine whether the recovery of peak torque more closely associates with maximal endurance exercise capacity than does the decline in peak torque at the end of the fatigue test. SUBJECTS: Thirty-three nondisabled subjects, ranging in age from 23 to 34 years (X = 27, SD = 3.4), participated in the reliability portion (phase 1) of the study. A different group of 21 nondisabled subjects, ranging in age from 21 to 47 years (X = 27.5, SD = 5.2), participated in the correlational portion (phase 2) of the study. METHODS: The short-term reliability of percentage of decline in peak torque and recovery of peak torque was assessed in phase 1. Each subject performed two quadriceps femoris muscle fatigue tests (test-retest) on an isokinetic dynamometer. In phase 2, each subject performed a single fatigue test and a test of maximal oxygen uptake (VO2max) to examine the relationships between VO2max and percentage of decline in peak torque at the end of the fatigue test and recovery of peak torque. RESULTS: Intraclass correlation coefficient values at every 30-second interval during recovery were acceptable (ICC = .67-.87), indicating recovery of peak torque is a consistent measure of quadriceps femoris muscle performance. A high negative correlation (r = -.84) was found between the percentage of decline at 30 seconds of recovery and VO2max, but a lower negative correlation (r = -.48) was found between the percentage of decline in torque at the end of the fatigue test and VO2max. CONCLUSION AND DISCUSSION: These results suggest recovery of peak torque is a reliable measure of muscle performance and closely associates with maximal aerobic exercise capacity.

Adult↗

PubMed1994

Shin splints and forefoot contact running: a case report.

Many athletes develop shin splints after athletic activity. The purpose of this case report is to describe the treatment of a patient with posteromedial tibial pain (shin splints) who habitually ran with a forefoot contact running style. The 20-year-old male patient, who played volleyball and basketball about 7 hours a week, complained of pain in the middle one-third of the posteromedial tibia after an acute but prolonged episode of running. Routine observational analysis and in-shoe pressure analysis of the patient's running style showed that he habitually ran on his toes with an absence of heelstrike (forefoot contact running). After instructing the patient on heel-toe running, he no longer complained of posteromedial tibial bone pain. Several possible reasons are proposed for the reduction of leg pain following cessation of forefoot contact running. This case report proposes forefoot contact running as a possible contributor to posteromedial shin splints and that a change in running style may be the optimal treatment for some patients.

Adult↗

PubMed1993

Histochemical and physiological correlates of training- and detraining-induced changes in the recovery from a fatigue test.

BACKGROUND AND PURPOSE: The primary purpose of this study was to evaluate the effects of endurance training and detraining on the development of and recovery from fatigue induced by isokinetic exercise. It was our hypothesis that the rate of recovery from fatigue would correlate with maximal oxygen uptake (VO2max). A secondary purpose was to determine whether changes in the development of fatigue and in the time course of recovery that occur with alterations in training status correlate with shifts in the proportions of type IIa and type IIb muscle fibers. SUBJECTS AND METHODS: Four subjects with no regular endurance exercise training participated in a 12-week program of intense endurance exercise training, and 6 endurance-trained subjects stopped all exercise training for 12 weeks. In addition, 11 subjects performed a single isokinetic fatigue test with recovery and a graded treadmill or bicycle ergometer test to determine VO2max. RESULTS: Maximal oxygen uptake increased 24% (SD = 10%) in response to the exercise training program and decreased 17% (SD = 6%) with detraining. The percentage of type IIa and type IIb muscle fibers changed with endurance training and detraining. The percentage of decline in torque during a 60-second isokinetic exercise test was unaffected by endurance training or detraining; however, there was a significant change in recovery of torque. CONCLUSION AND DISCUSSION: The results demonstrate a positive correlation (r = .75) between the percentage of reduction in torque at 30 seconds of recovery and the change in the proportion of type IIb fibers with both training and detraining. The results also demonstrate a high, negative correlation (r = -.84) between the percentage of reduction in torque at 30 seconds of recovery and VO2max. These results suggest the recovery of muscle torque reflects both the training- and detraining-induced changes in the proportion of type IIa and type IIb muscle fibers and maximal aerobic exercise capacity.

Adult↗

PubMed1993

The role of skeletal muscle in glucose transport, glucose homeostasis, and insulin resistance: implications for physical therapy.

Skeletal muscle has a fundamentally important role in the maintenance of normal glucose homeostasis and in regulating whole-body carbohydrate metabolism. In this review, we discuss the regulation of skeletal muscle glucose transport by muscular activity and inactivity. A large number of patients routinely seen by physical therapists exhibit some form of skeletal muscle insulin resistance. Therefore, we discuss how skeletal muscle insulin resistance can be localized to a relatively small muscle mass, or in other circumstances can affect a large proportion of the muscle mass leading to disturbances in whole-body glucose homeostasis. We review the mechanisms and regulation of skeletal muscle glucose transport as background for understanding how defects in this process may contribute to the underlying pathogenesis of insulin resistance. Research into the events regulating glucose entry into skeletal muscles has considerable impact on how physical therapy exercise prescriptions may benefit patients with disturbances in carbohydrate metabolism. With an understanding of the principles of proper exercise prescription, physical therapists can use exercise training as a primary therapeutic intervention to improve local muscle and whole-body glucose utilization, and thereby minimize insulin resistance.

Blood Glucose↗

PubMed1990

Type II fiber activation with electrical stimulation: a preliminary report.

Electrical stimulation to augment or maintain muscle performance has been well documented. The purpose of this preliminary report is to present the results of a single-case study conducted to determine the order of activation of skeletal muscle fibers as a result of electrical stimulation. The subject's quadriceps femoris muscles were electrically stimulated at 80% of maximal isometric torque. Pre-stimulation and immediate post-stimulation muscle biopsy samples were obtained, and a modification of the glucogen-depletion method was used to determine activation of muscle fibers. The pre-stimulation muscle biopsy sample demonstrated uniform periodic acid-Schiff (PAS)-positive staining in all fiber types, whereas the post-stimulation muscle biopsy sample showed glycogen depletion of type II muscle fibers. The most PAS-negative muscle fibers were type IIa skeletal muscle fibers. The results of this single-case study provide evidence that electrical stimulation, as described, selectively activates type II skeletal muscle fibers. The implication of this finding is that, in many chronic diseases, type II fibers are selectively and preferentially affected. Electrical stimulation may be a clinically viable technique to use in patients with type II fiber involvement.

Adult↗

PubMed1989

Reliability of a diabetic foot evaluation.

The purpose of this study was to establish the interrater and intrarater reliability of various ankle and foot measures common to a diabetic evaluation. Bilateral biomechanical, sensory, and wound-size measurements were obtained in 31 subjects with diabetes mellitus. Twenty-five subjects were retested by the initial examiner to determine intratester reliability, and all subjects were retested by another examiner to determine intertester reliability. Both examiners participated in an extensive training period prior to the initiation of this study to minimize variability between and within measurers. Intraclass correlation coefficients for interrater and intrarater measurements ranged from .58 to .89 and from .74 to .99, respectively. The results of this study indicate that ankle and foot measurements common to a diabetic evaluation can be taken reliably between testers. We believe extensive examiner training in these clinically relevant measures can improve reliability between testers.

Adult↗

PubMed1989

Insensitivity, limited joint mobility, and plantar ulcers in patients with diabetes mellitus.

The purpose of this study was to determine whether differences in sensation, ankle dorsiflexion (DF), and subtalar joint (STJ) motion exist between 1) diabetic patients with a history of plantar ulcer (DMW Group), 2) diabetic patients without a history of plantar ulcer (DMWO Group), and 3) a nondiabetic control group (NDC Group). There were 23, 23, and 24 subjects in the respective groups. The mean age for each group was 58, 63, and 60 years, respectively. The mean DF for each group was 2, 5, and 7 degrees, respectively, and the mean STJ motion was 26, 31, and 35 degrees, respectively. Mode values for sensation with Semmes-Weinstein monofilaments were 6.10, 5.07, and 4.17. The results indicate the DMW Group had significantly less sensation, DF, and STJ motion than the NDC Group (p less than .05). In the DWM Group, the ulceration was seen more often on the side with least motion. Limited DF and STJ motion may restrict the foot's ability to absorb shock and transverse rotation, contributing to the pathogenesis of plantar ulceration in the insensitive foot. Although these results demonstrate an association, not a causative relationship, we believe diabetic patients should be screened routinely for insensitivity and limited joint mobility at the feet and appropriate preventive measures should be taken.

Adolescent↗

PubMed1989

Total contact casting in treatment of diabetic plantar ulcers. Controlled clinical trial.

This study compared the treatment of total contact casting (TCC) with traditional dressing treatment (TDT) in the management of diabetic plantar ulcers. Forty patients with diabetes mellitus and a plantar ulcer but with no gross infection, osteomyelitis, or gangrene were randomly assigned to the TCC group (n = 21) or TDT group (n = 19). Age, sex, ratio of insulin-dependent diabetes mellitus to non-insulin-dependent diabetes mellitus, duration of diabetes mellitus, vascular status, size and duration of ulcer, and sensation were not significantly different between groups (P greater than .05). In the experimental group, TCC was applied on the initial visit, and subjects were instructed to limit ambulation to approximately 33% of their usual activity. Subjects in the control group were prescribed dressing changes and accommodative footwear and were instructed to avoid bearing weight on the involved extremity. Ulcers were considered healed if they showed complete skin closure with no drainage. Ulcers were considered not healed if they showed no decrease in size by 6 wk or if infection developed that required hospitalization. In the TCC group, 19 of 21 ulcers healed in 42 +/- 29 days; in the TDT group, 6 of 19 ulcers healed in 65 +/- 29 days. Significantly more ulcers healed (chi 2 = 12.4, P less than .05) and fewer infections developed (chi 2 = 4.1, P less than .05) in the TCC group. We conclude TCC is a successful method of treating diabetic plantar ulcers but requires careful application, close follow-up, and patient compliance with scheduled appointments to minimize complications.

Casts, Surgical↗

PubMed1987

Diabetic plantar ulcers treated by total contact casting. A clinical report.

The purpose of this clinical report is to describe the healing times of plantar ulcers treated by total contact casting (TCC) in nondiabetic and diabetic patients with and without evidence of severe peripheral vascular disease. Thirty patients with 33 chronic plantar ulcers were treated by applying total contact walking casts. Results demonstrate that 27 of 33 ulcers (81.8%) healed in an average time of 43.6 days. Healing times of patients with severe peripheral vascular disease secondary to diabetes mellitus are similar to those of patients without evidence of vascular disease. These results indicate that TCC is an effective and rapid treatment for chronic plantar ulcers in patients with or without vascular compromise secondary to diabetes mellitus. In addition, the results suggest that pressure reduction on the insensitive foot should be considered in treatment.

Casts, Surgical↗

PubMed1987

Molded double-rocker plaster shoe for healing a diabetic plantar ulcer. A case report.

The purpose of this case report is to document the successful healing of a chronic neuropathic plantar ulcer with the molded double-rocker plaster shoe (MDRPS) in a lower extremity that also had stasis changes and poor blood flow. The patient was a 67-year-old woman with insulin-dependent diabetes mellitus, insensitive feet, a right ankle-arm index of 0.48, and an ulcer beneath the right cuneonavicular joint measuring 0.94 cm2 in area and 2 mm deep. Reported onset of the ulcer was 10 months before referral for physical therapy. The MDRPS was chosen as an alternative treatment to conventional below-knee total contact casting (TCC) because of the stasis changes and fragile skin in the patient's lower extremities. The ulcer healed in 39 days after initiating treatment with the MDRPS. We consider the MDRPS the preferred treatment with those patients with neuropathic plantar ulcers who cannot tolerate the below-knee TCC.

Aged↗

PubMed1987

Electrically elicited fatigue test of the quadriceps femoris muscle. Description and reliability.

The purposes of this study were to develop an electrically elicited fatigue test (EEFT) that uses electrically elicited isometric muscle contractions and to examine the reliability of this test on a group of healthy individuals. Fifteen subjects were tested on two occasions, one week apart. The subjects were seated and the left leg secured to an isokinetic dynamometer with the knee positioned at 45 degrees of flexion. Maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle was obtained and resultant knee extension torque was recorded. The quadriceps femoris muscle then was stimulated 50 times at the current level that elicited a knee extension torque level equal to 60% of that obtained during the MVIC. Percentages of decline in torque were calculated. Test-retest reliability indexes were calculated for the means of contractions 21 to 25 (r = .82, ICC = .83) and for contractions 46 to 50 (r = .92, ICC = .82). The EEFT was found to be reliable and may provide a clinically applicable means of measuring peripheral muscle fatigue.

Adult↗

PubMed1986

Hamstring muscle strain treated by mobilizing the sacroiliac joint.

The purpose of this study was to compare the effectiveness of two types of treatment of hamstring muscle strains. Twenty patients with hamstring muscle strains were assigned randomly to an Experimental Group (n = 10) or a Control Group (n = 10). Peak torque production of the quadriceps femoris and hamstring muscles and hamstring muscle length were measured before and after treatment. The hamstring muscles of the Experimental and Control groups were treated with moist heat followed by passive stretching. The Experimental Group also received manipulation of the sacroiliac joint. The change in hamstring muscle peak torque was significantly greater for the Experimental Group than for the Control Group (p less than .005). No significant differences existed between the two groups in either quadriceps femoris muscle peak torque or hamstring muscle length. The results of this study suggest a relationship between sacroiliac joint dysfunction and hamstring muscle strain.

Adolescent↗

PubMed1984

Effect of weight training on blood pressure and hemodynamics in hypertensive adolescents.

Six adolescents with persistent essential hypertension were examined to determine the effect of weight training on their blood pressure and hemodynamics. Five had first completed an endurance training program; one subject trained only by weight lifting. All subjects were reevaluated after 5 +/- 2 months of weight training, and 12 +/- 2 months after cessation of training. Endurance training resulted in an increase in VO2max and decreases in systolic and diastolic blood pressure. After weight training, VO2max had decreased to the level found prior to endurance training, and body weight was significantly increased. Systolic blood pressure after weight training was 17 +/- 4 mm Hg lower than when measured initially (P less than 0.01). Weight training maintained the reduction in diastolic pressure elicited by endurance exercise in those who initially had diastolic hypertension. Cessation of all forms of training resulted in no change in body weight, body fat, or VO2max from the values measured after weight training. Systolic pressure increased significantly with the cessation of training to a value not different from that measured initially. Diastolic pressure also increased after cessation of training, but was still below the initial value. The only significant hemodynamic change found was a reduction in systemic vascular resistance in response to weight training. Weight training in hypertensive adolescents appears to maintain the reductions in blood pressure achieved by endurance training, and may even elicit further reductions in blood pressure.

Adipose Tissue↗

PubMed1984

Time course of loss of adaptations after stopping prolonged intense endurance training.

Seven endurance exercise-trained subjects were studied 12, 21, 56, and 84 days after cessation of training. Maximal O2 uptake (VO2 max) declined 7% (P less than 0.05) during the first 21 days of inactivity and stabilized after 56 days at a level 16% (P less than 0.05) below the initial trained value. After 84 days of detraining the experimental subjects still had a higher VO2 max than did eight sedentary control subjects who had never trained (50.8 vs. 43.3 ml X kg-1 X min-1), due primarily to a larger arterial-mixed venous O2 (a-vO2) difference. Stroke volume (SV) during exercise was high initially and declined during the early detraining period to a level not different from control. Skeletal muscle capillarization did not decline with inactivity and remained 50% above (P less than 0.05) sedentary control. Citrate synthase and succinate dehydrogenase activities in muscle declined with a half-time of 12 days and stabilized at levels 50% above sedentary control (P less than 0.05). The initial decline in VO2 max was related to a reduced SV and the later decline to a reduced a-vO2 difference. Muscle capillarization and oxidative enzyme activity remained above sedentary levels and this may help explain why a-vO2 difference and VO2 max after 84 days of detraining were still higher than in untrained subjects.

Adaptation, Physiological↗

PubMed1983

Muscle function in rheumatic disease patients treated with corticosteroids.

Clinical and experimental data indicate that long-term corticosteroid use leads to atrophy of the type 2 muscle fibers. The purpose of this study was to characterize and quantify the nature of muscle function in rheumatic disease patients who have been on long-term corticosteroid therapy. Quadriceps function (i.e., peak torque and power) in 19 patients (11 with rheumatoid arthritis, five with systemic lupus erythematosis, and 3 other) and 11 age- and activity-matched normal controls was measured with an isokinetic dynamometer (Cybex II), during four constant velocity movements. Power was significantly lower for the patients at all speeds. At the higher speeds the patients' deficit in power production increased as indicated by a difference in the slopes of power-velocity regression lines. Measures of peak torque could not be consistently used to differentiate the groups. Patients with rheumatic diseases receiving corticosteroids have a decreased ability to generate muscle power. The method described allows for quantification of these deficits in a clinical setting.

Adrenal Cortex Hormones↗

PubMed1983

Electromyographic, peak torque, and power relationships during isokinetic movement.

The use of isokinetic measurements for research and clinical practice becomes more meaningful when it can be demonstrated that subjects being tested at multiple velocities are making similar efforts and when the relationships between various biomechanical measures are understood. The purpose of this study was to examine 1) integrated electromyographic activity per second of the quadriceps femoris muscle at four isokinetic speeds (30, 60, 90, and 120 degrees/sec) and 2) the relationship of power to peak torque at each speed. Two groups were tested: "normals" (healthy subjects) and patients undergoing long-term steroid therapy for rheumatic diseases. The integrated electromyographic activity per second did not vary significantly across speeds, indicating that subjects in each group made equivalent efforts at all four speeds. At each speed, for each group, high correlations were found between peak torque and power. Population-specific and speed-specific linear regression equations were calculated that allowed for predictions of power from the more easily obtained clinical measure of peak torque.

Adult↗

PubMed1983

Effect of damp on isokinetic measurements.

Meaningful use of isokinetic data requires understanding potential sources of variation and error. The purpose of this study was to examine one possible source of variation: the effect of recorder damp settings on Cybex II torque tracings. The effect of damp settings 0 through 4 at speeds of 30 degrees/sec and 75 degrees/sec was assessed by dropping loads of 13.65 kg and 36.85 kg attached to a lever arm of 30.5 cm on a Cybex II. The effect of damp settings at 180 degrees/sec was examined with the same weights at damp settings 2 and 4. Increasing damp resulted in 1) a decrease in amplitude of the entire torque curve and a decreased measurement of peak torque and 2) a shift of the torque curve to the right (later in time). The data underscore the need to record and to report the damp settings used during isokinetic testing.

Electronics, Medical↗

PubMed1983

Failure of endurance training to alter the cardiovascular response to static contraction.

The purpose of this study was to determine whether endurance training alters the cardiovascular response to static contractions of the trained, but not untrained, musculature. Six healthy, untrained males (aged 23-36 years) underwent 10-12 weeks of intensive training involving both cycling and running. Peak VO2 on the bicycle ergometer, VO2max during graded treadmill running and concentrations of citrate synthase (CS) and malate dehydrogenase (MDH) in the vastus lateralis muscle were measured before and after training. Subjects performed static leg extension and forearm extension at 30% of maximal voluntary contraction until exhaustion before and after training. Heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure were measured at rest, and in addition to perceived exertion (PE), every 30 s during contraction. Endurance training elicited significant increases in peak VO2 (36%), VO2max (32%), CS (25%) and MDH (42%) (all P less than 0.05). HR at rest was significantly lower (P less than 0.05) after training, while SBP and DBP were unchanged. HR, SBP, DBP and PE increased throughout both types of static contractions. However, the magnitude of the increases were unaffected by training. In contrast to recent findings, these results suggest that the increases in heart rate and blood pressure in response to static contraction are not altered after endurance training in either the trained or the untrained muscle groups.

Adult↗