摘要:

AbstractEditor-in-Chief Note: In the March 1992 issue (24:270–280, 1992), we initiated the Commentary Section ofMedicine and Science in Sports and Exercisewith a commentary by Robert C. Cantu, M.D., concerning the fact that congenital cardiovascular disease was becoming the major cause of athletic death in high school and college. In my opinion the following commentary by Paul D. Thompson, M.D., provides a statistical base upon which the preparticipation physical can be analyzed to determine when to include a referral for the more expensive cardiovascular evaluation.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTMAFFULLI, N., V. TESTA, and: G. CAPASSO. Mediopatellar synovial plica of the knee in athletes: results of arthroscopic treatment. Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 985–988, 1993. The long-term results (9–87 months) of the arthroscopic treatment of unilateral mediopatellar synovial plica of the knee in 102 athletes are reported. In all patients a large and/or fibrotic inflamed mediopatellar plica impinging on the femoral condyle on knee flexion was identified and trimmed. Chondromalacia patellae was detected in 38 patients. The impingement lesion was seen in 13 knees. In one patient, a minor tear of the lateral meniscus was trimmed, and one patient was found to suffer from a clinically asymptomatic partial tear of the anterior cruciate ligament. Isometric strength testing of the quadriceps revealed marked decrease at the second postoperative week, with subsequent gradual recovery. The results obtained justify arthroscopic treatment in a young, extremely active population.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

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AbstractBOCKRATH, K., C. WOODEN, T. WORRELL, C. D. INGERSOLL, and J. Farr. Effects of patella taping on patella position and perceived pain.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 989–992, 1993. Anterior knee pain syndrome (AKPS) represents a significant challenge for the sports medicine clinician. One proposed etiological factor for AKPS is poor vastus medialis obliquus (VMO) control, resulting in lateral glide of the patella. Patella taping has been advocated to increase VMO control. The purpose of this study was to determine the effects of patella taping on patella position and perceived pain. Twelve subjects (age = 29 ± 9 yr; weight= 70.9 kg ± 17.8; height = 174.0 cm ± 8.1) with AKPS currently using patella taping procedures with a decrease in their symptoms participated. Each subject had Merchant's view x-rays taken pre- and posittaping while performing an isometric quadriceps contraction to determine patella rotation and patella congruency angles. Subjects also completed a visual analog pain scale after performing a 0.2 m (8“) step-down both pre- and posttaping. Pairedt-tests revealed no significant change in patellofemoral congruency (P= 0.98) and patella rotation angles (P= 0.80). Significant reduction (50%) in subject pain level was revealed by the visual analog scale (t(15) = 4.99;P< 0.0005). Results demonstrate that patella taping significantly reduced the perceived pain levels during a 0.2-m step-down; however, this reduction in pain was not associated with patella position changes.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTPIVARNIK, J. M., N. A. AYRES, M. B. MAUER, D. B. COTTON, B. KIRSHON, and G. A. DILDY. Effects of maternal aerobic fitness on cardiorespiratory responses to exercise.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 993–998, 1993. We hypothesized that aerobically fit women who continued to exercise throughout pregnancy would have enhanced cardiorespiratory responses to exercise. Physically active (N= 10) and sedentary (N= 6) subjects were compared during steady-state (15 min) semi-recumbent cycle exercise performed at a given heart rate (HR; 140 b·min−1) twice during pregnancy (25 wk, 36 wk) and 12 wk postpartum. Indirect calorimetry was used to measure volumes and fractional concentrations of expired gases. Cardiac output was estimated via CO2rebreathing. Data were analyzed with repeated measures ANOVA. Caloric expenditure during exercise was significantly (P< 0.001) greater in the physically active (7.2 kcal·min−1) compared with sedentary (4.7 kcal·min−1) subjects. Alveolar ventilation and cardiac output responses to exercise were proportionally greater (P< 0.001) in the aerobically fit subjects. Ventilatory equivalents for O2and physiological dead space/tidal volume ratios were significantly (P< 0.01) lower in the physically active subjects during exercise. In contrast, ratings of perceived exertion during exercise did not differ between subject groups. It appears that a physically active woman's enhanced cardiorespiratory responses to acute exercise are maintained during pregnancy if she continues her aerobic fitness program throughout gestation.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTKANDARIAN, S. C. and J. H. WILLIAMS. Contractile properties of skinned fibers from hypertrophied skeletal muscle.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 999–1004, 1993. We have previously shown deficits in specific tension (N·cm−2) in whole hypertrophied skeletal muscle (18–30%). The purpose of the present study was to determine if this intrinsic deficit exists in chemically skinned, hypertrophied single fibers, and also to measure their Ca2+sensitivity. One group of rats (N= 4) had bilateral surgical ablation o the gastrocnemius and soleus muscles, and another group (N= 4) had the gastrocnemius and plantaris muscles ablated to induce hypertrophy in the plantaris and soleus muscles, respectively. Thirty days after surgery five fibers were dissected and analyzed from each of eight muscles per group, including control muscles. In hypertrophied plantaris and soleus muscles, fiber cross-sectional area (CSA) was 20% and 29% greater, respectively, than control values. Maximal Ca2+activated tension (Po, pCa 4.5) was 15% greater in hypertrophied plantaris fibers and 18% greater in hypertrophied soleus fibers compared with respective control values (PP< 0.05). Regarding Ca2+sensitivity, the Ca2+concentration to elicit 50% of Po (i.e., pCa50) was significantly lower in hypertrophied soleus (58%) and plantaris (29%) fibers. This leftward shift in the force-pCa curve reflects greater Ca2+sensitivity in hypertrophied fibers. Since the single fiber Po/CSA was only slightly decreased, these data suggest that during tetanic stimulation of whole muscle Ca2+delivery to the contractile apparatus may be impaired. The shift in the force-pCa curve may reflect alterations in myofibrillar proteins known to affect Ca2+sensitivity, and/or changes in the kinetics of cross-bridge cycling.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTCZERWINSKI, S. M., J. NOVAKOFSKI, and P. J. BECHTEL. Modulation of IGF mRNA abundance during muscle denervation atrophy.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 1005–1008, 1993. Changes in skeletal muscle activity cause dramatic alterations in muscle mass. Increased load on a muscle (synergistic overload) results in muscle hypertrophy. During hypertrophy, skeletal muscle concentrations of insulin-like growth factors (IGF-I and IGF-II) mRNAs increase. To clarify the role of IGFs in regulating muscle mass, this study examined whether IGF-II and -II mRNA levels were altered during decreased muscle activity (denervation). Gastrocnemius weights decreased 4.2%, 7.7%, 18.1%, 27.7%, 35.1%, 45.0%, and 60.3% at 2, 3, 5, 7, 10, 12, and 17 d following denervation, respectively. Muscle DNA content remained constant throughout the first 12 d after surgery, but increased above control levels at day 17. During the first week after surgery, gastrocnemius IGF-II mRNA remained constant. However, IGF-II mRNA abundance was 2.5-fold greater than controls by 10 d of denervation, 3-fold by 12 d, and 6.8-fold by 17 d. On the other hand, IGF-I mRNA levels were not affected by denervation. In conclusion, although increased muscle activity results in a change of IGF-I mRNA expression, decreased muscle activity has no effect on IGF-I mRNA expression. In contrast, IGF-II mRNA levels increase with long-term denervation as well as with increased muscle activity. This study suggests that muscle activity may not be the only factor affecting IGF-I and -II expression.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTO'BRIEN, M. J., C. A. VIGUIE, R. S. MAZZEO, and G. A. BROOKS. Carbohydrate dependence during marathon running.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 1009–1017, 1993. To test the hypothesis that marathon running is dependent on lipid oxidation, 12 post-absorptive males (31.9 ± 2.1 yr) ran a treadmill marathon and substrate utilization was assessed. Subjects were placed into a fast (F ≤ 2 hr, 45 min; 73.3% &OV0312;O2max), or a slow (S ≤ 3 hr, 45 min; 64.5% &OV0312;O2max) marathon group. The day before testing subjects rested, but ate their normal diet. Subjects were tested in the morning after an overnight fast, and only tap water, at a rate of 1 1·h, was ingested during exercise. Blood glucose concentration rose at exercise onset, peaked at approximately an hour, but then decreased over time remaining at or above resting-levels. Free fatty acids and glycerol rose continuously. No significant differences in plasma FFA, glycerol, or blood glucose concentrations were observed between F or S groups during the marathon. Mean blood lactate concentration was significantly higher (P< 0.05) in the F (2.1 ± 0.3 mM) group than the S (1.2 ± 0.2 mM) during exercise. Mean plasma epinephrine was significantly higher in the F (0.9 ± 0.2 ng·ml−1) than the S (0.6 ± 0.2 ng·ml−1) group; norepinephrine was also higher in F (3.9 ± 1.4 ng·ml−1) than the S (2.5 ± 0.9 ng·ml−1,P≤ 0.05). Blood lactate and epinephrine concentrations correlated significantly (r = 0.76 and 0.78 in F and S groups, respectively). The average respiratory gas exchange ratio (R = VCO2/&OV0312;2) was higher in F (0.99 ± 0.01) than S (0.90 ± 0.01, P ≤ 0.05). A direct relationship between carbohydrate oxidation and running speed during marathon running is indicated. Estimated carbohydrate combustion [(F: 2,414.3 ± 43.0 kcal (575 ± 10 g); S: 2,890.0 ± 159.0 kcal (688 ± 38 g)] exceeded estimated glycogen stores in active muscle and liver (475 g = 375 g (muscle) + 100 g (liver)]. Therefore, total body glycogen stores were made available for combustion. All classes of energy substrates participate, but carbohydrate, not lipid, is the primary fuel for marathon running.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTHEALTH, E. M., A. R. WILCOX, and C. M. QUINN. Effects of nicotinic acid on respiratory exchange ratio and substrate levels during exercise.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 1018–1023, 1993. The purpose of this study was to investigate the effects of pharmacologic treatment with nicotinic acid (NA) (3 g NA·d−1) on fuel utilization during exercise and on total and HDL-cholesterol levels of trained runners. Eight experienced male runners performed four 30-min submaximal treadmill runs (SUB) at approximately 60% of aerobic capacity: the first served as the control condition, whereas SUBs 2, 3, and 4 were conducted at the onset, midpoint, and conclusion of the 3-wk NA treatment period. A 1-g NA dose was ingested 1 h prior to SUBs 2–4, which were conducted in the morning following a 12-h fast. The respiratory exchange ratio (RER) was significantly higher during SUBs 2, 3, and 4 (0.919 ± 0.009,0.898 ± 0.007, and 0.896 ± 0.009, respectively) than during SUB1 (0.871 ± 0.008); and the RER during SUB2 was also significantly higher than that during SUB3 and SUB4 (P< 0.001). Serum free fatty acid (FFA) and glycerol levels were significantly lower during SUBs 2, 3, and 4 as compared with SUB1 (P< 0.001). Total cholesterol showed a significant decrease (from 195.3 ± 9.2 to 174.5 ± 9.2 mg·dl−1) and HDL cholesterol showed a significant elevation (from 56.2 ± 2.9 to 63.0 ± 3.9 mg·dl−1) during the NA treatment period (P

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTSHI, X., C. G. CRANDALL, J. T. POTTS, J. W. WILLIAMSON, B. H. FORESMAN, and P. B. RAVEN. A diminished aortic-cardiac reflex during hypotension in aerobically fit young men.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 1024–1030, 1993. We compared the aortic-cardiac baroreflex sensitivity in eight average fit (AF: &OV0312;2max= 44.7 ± 1.3 ml·kg−1·min−1) and seven high fit (HF: &OV0312;2max= 64.1 ± 1.7 ml·min−1·kg−1) healthy young men during hypotension elicited by steady state sodium nitroprusside (SN) infusion. During SN mean arterial pressure (MAP) was similarly decreased in AF (-12.6 ± 1.0 mm Hg) and HF (-12.1 ± 1.1 mm Hg). However, the increases in heart rate (HR) were less (PP> 0.05) was applied to counteract the decreased carotid sinus transmural pressure during SN, thereby isolating the aortic baroreceptors, the increased HR remained less (P−1) than HF (1.2 ± 0.2 and 0.6 ± 0.2 bpm·mm Hg−1). However, the estimated carotid-cardiac baroreflex sensitivity (i.e., the gain difference between the stage SN and SN+NS) was not different between AF (0.7 ± 0.2 bpm·mm Hg−1) and HF (0.6 ± 0.1 bpm·mm Hg−1). These data indicated that the aortic-cardiac baroreflex sensitivity during hypotension was significantly diminished with endurance exercise training.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

ABSTRACTBERRY, M. J., J. A. STORSTEEN, and C. M. WOODARD. Effects of body mass on exercise efficiency and &OV0312;2during steady-state cycling.Med. Sci. Sports Exerc., Vol. 25, No. 9, pp. 1031–1037, 1993. Oxygen uptake (&OV0312;2) and exercise efficiency during cycle ergometer exercise are considered to be independent of body mass. To determine the validity of this assumption, 50 females ranging in body mass from 41.5–98.9 kg exercised on a cycle ergometer with no load at 60 rpm and at 25, 50, 75, and 100 W at 60 and 90 rpm. Gross &OV0312;2and efficiency, net &OV0312;2and efficiency, work &OV0312;2and efficiency, and delta efficiency were computed. Gross and net &OV0312;2were significantly and positively correlated with body mass at all work rates and pedal frequencies. Gross efficiency was significantly and negatively correlated with body mass at all work rates and pedal frequencies. Work &OV0312;2and body mass were not significantly correlated. The correlations between work and delta efficiency and body mass were not significant. Since body mass was found to be significantly correlated with gross &OV0312;2, the following equation was developed using stepwise multiple regression to predict gross &OV0312;2: &OV0312;2(ml·min−1) = 10.9 (work rate, W) + 8.2 (pedal rate, rpm) + 8.3 (body mass, kg) = 559.6. These data suggest that body mass should be considered when estimating the oxygen uptake during cycle ergometer exercise.

ISSN:0195-9131    

出版商:OVID    

年代:1993

数据来源: OVID