摘要:

HORRIGAN, J. M., F. G. SHELLOCK, J. H. MINK, and A. L. DEUTSCH. Magnetic resonance imaging evaluation of muscle usage associated with three exercises for rotator cuff rehabilitation.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1361–1366, 1999.Purpose:Methods of determining muscle usage for exercises involving rotator cuff muscles are limited. Therefore, this investigation used magnetic resonance imaging (MRI) to evaluate the effect of three different exercises used for rehabilitation of the rotator cuff.Methods:Five normal volunteer subjects (3 men, 2 women, mean age 31.4 yr) were studied. The exercises were scaption with internal rotation (SIR), military press (MP), and side-lying 45° abduction (SLA). MR imaging was performed immediately before and after exercise using a “fast” spin echo STIR sequence and oblique coronal plane imaging. Changes in signal intensity pre- and post-exercise were measured at comparable section locations for the MR images of the supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, and trapezius.Results:The SLA showed the greatest increase in signal intensity in all the muscles (percent change,P< 0.01) except for the trapezius, which was used more by the MP and SIR. None of the exercises activated the teres minor (percent change,P= not significant).Conclusion:These findings have important implications in efficacy of physical rehabilitation of the rotator cuff and avoidance of subacromial impingement exercise motions.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

SALLIS, R. and C. M. CHASSAY. Recognizing and treating common cold-induced injury in outdoor sports.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1367–1373, 1999. We briefly review the physiology of cold exposure, the spectrum and prevention of common cold-induced injuries (especially in athletes participating in outdoor sports), and the potentially harmful side effects of localized cryotherapy. Severe cold affects all organ systems and especially the central nervous and cardiovascular systems; many biochemical reactions and pathways become distorted or slowed at low body core temperatures and can thus affect athletic performance. Low body shell temperature, too, can interfere with athletic ability by weakening and slowing muscle contractions, by delaying nerve conduction time, and by facilitating injury. Cold-induced injuries may be local or systemic, but they can usually be prevented by knowledge, good physical condition, appropriate nutrition and equipment, and avoidance of moisture.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

MCCRORY, J. L., D. F. MARTIN, R. B. LOWERY, D. W. CANNON, W. W. CURL, H. M. READ, JR., D. M. HUNTER, T. CRAVEN, and S. P. MESSIER. Etiologic factors associated with Achilles tendinitis in runners.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1374–1381, 1999.Purpose:The purpose of this study was to determine whether relationships exist between selected training, anthropometric, isokinetic muscular strength, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with Achilles tendinitis.Methods:Specifically, we examined differences in selected measures between a noninjured cohort of runners (N= 58) and a cohort of injured runners with Achilles tendinitis (N= 31). Isokinetic, kinetic, and kinematic measures were collected using a Cybex II+ isokinetic dynamometer (Medway, MA), AMTI force plate (500 Hz), and Motion Analysis high-speed videography (200 Hz), respectively. Separate discriminant function analyses were performed on each of the five sets of variables to identify the factors that best discriminate between the injured and control groups.Results:Years running, training pace, stretching habits (injured runners were less likely to incorporate stretching into their training routine), touchdown angle, plantar flexion peak torque at 180°·s−1, and arch index were found to be significant discriminators.Conclusion:A combined discriminant analysis using the above mentioned significant variables revealed that plantar flexion peak torque, touchdown angle, and years running were the strongest discriminators between runners afflicted with Achilles tendinitis and runners who had no history of overuse injury.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

DALE, K. S., and D. M. LANDERS. Weight control in wrestling: eating disorders or disordered eating?Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1382–1389, 1999.Purpose:Several recent studies have pointed out that the weight loss techniques used by wrestlers to make weight are similar to the behavior of bulimics. The purpose of this study was to determine whether an increased risk of bulimia nervosa existed for a group of junior high and high school wrestlers.Methods:Wrestlers (N= 85) completed the Eating Disorder Inventory (EDI) once during the season, and once during the off-season. A comparison group of nonwrestlers (N= 75) also completed the questionnaire.Results:No significant differences were found between the number of in-season wrestlers and nonwrestlers classified as “at risk” for bulimia nervosa. Significant differences were revealed, however, between in-season wrestlers and nonwrestlers, and between in-season wrestlers and off-season wrestlers, on the Drive for Thinness subscale. In both cases, significantly more in-season wrestlers scored above the “at risk” cutoff on the subscale.Conclusions:These results indicate that although in-season wrestlers are more weight conscious than nonwrestlers, these feelings and attitudes are transient. All subjects classified as “at risk” also participated in an interview which followed the format of the Eating Disorder Examination. Interviews with in-season wrestlers revealed that their concerns with weight were due entirely to the demands of wrestling, and did not meet the severity level required for a diagnosis of bulimia nervosa.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

CASE, D., J. T. BAER, and M. T. R. SUBBIAH. The effect of prolonged exercise on lipid peroxidation in eumenorrheic female runners.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1390–1393, 1999.Purpose:Recently a protective role has been demonstrated for estrogens as free radical scavengers. In this study, lipid peroxidation was evaluated in eumenorrheic runners before and after participation in a half-marathon.Methods:Seven female runners who participated in regular training (average 25 miles·wk−1) and reported regular menses (12/yr) served as subjects. Subjects were all in a low estrogen phase of their menstrual cycle as confirmed by menstrual record and plasma estradiol level (42.71 ± 21.65 pg·mL−1). Low density lipoprotein oxidation (formation of conjugated dienes) was determined 2 h prerace and 5 min after subject’s completion of the race.Results:Results showed a significant increase in lag phase time of conjugated dienes after prolonged exercise (28.43 ± 4.89 min vs postrace 35.21 ± 4.32 min,P< 0.05). No correlation between mean levels of estradiol and mean lipid peroxidation levels at rest, 5 min after exercise, or difference (prepost) was observed.Conclusion:Prolonged endurance exercise does not appear to increase potential for lipid peroxidation in trained eumenorrheic runners during a low estrogen phase of the menstrual cycle.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BRINDLE, T. J., J. NYLAND, R. SHAPIRO, D. N. M. CABORN, and R. STINE. Shoulder proprioception: latent muscle reaction times.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1394–1398, 1999.Purpose:The purpose of this study was to identify electromyographic (EMG) differences in the latent muscle reaction timing (LMRT) of the rotator cuff between trained overhead throwers and control subjects in response to sudden internal rotation perturbation (P≤ 0.05).Methods:Subjects included 15 trained overhead throwers (male intercollegiate baseball players) and 15 untrained subjects (males not active in competitive throwing sports). Subjects were tested while seated, with their dominant glenohumeral joint positioned in 90° abduction/external rotation (scapular plane), their elbow flexed to 90°, and their forearm placed in the perturbation device. Rotator cuff LMRT was assessed as they tried to decelerate a variably timed, sudden internal rotation force. EMG sampling (2000 Hz, 2-s duration) began immediately before perturbation.Results:Trained throwers had slower infraspinatus (P= 0.011) and teres minor (P= 0.024) LMRT and decreased supraspinatus (P= 0.001) and posterior deltoid (P= 0.0001) muscle activation duration compared with control subjects.Conclusions:These results suggest that the rotator cuff muscles of trained throwers may be downregulated in response to sudden internal rotation perturbation. Although these adaptations would enable greater internal rotation velocities during overhead throwing, they may also contribute to glenohumeral joint pathology. The identification of changes in rotator cuff LMRT in response to sudden internal rotation perturbation suggests an area of acquired neuromuscular imbalance warranting consideration by those involved in the rehabilitation and conditioning of the overhead throwing athlete.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

SHEEHAN, F. T. and J. E. DRACE. Quantitative MR measures of three-dimensional patellar kinematics as a research and diagnostic tool.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1399–1405, 1999.Purpose:A three-dimensional (3D) study of normal patellar-femoral-tibial (knee) joint kinematics was performed using Cine Phase Contrast Magnetic resonance imaging (Cine-PC MRI) to determine the utility of this technique as a diagnostic tool in defining alterations in patellar tracking.Methods:Cine-PC MRI was originally developed to measure heart motion and blood flow and has now been adapted to the study of the musculoskeletal system. Thus, for the first time knee joint kinematics can be studied three-dimensionally, noninvasively, andin vivoduring dynamic volitional leg extensions under load. Cine-PC MRI provides one anatomic and three orthogonal velocity images (vx, vy, and vz) for each time frame within the motion cycle. Bone displacements are calculated using integration and are then converted into both 3D orientation angles and 2D clinical angles.Results:The 3D patellar tilt and 2D clinical patellar tilt angle were nearly identical, even though these two angles have distinct mathematical definitions. The precision of the 2D clinical patellar tilt angle (N= 3) was approximately 2.4°.Conclusions:Since the overall subject (N= 18) variability for clinical patellar tilt angle and medial/lateral patellar displacement was low (SD = 2.9° and 3.3 mm, respectively), Cine-PC MRI could prove to be a valuable tool in studying subtle changes in patellar tracking.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

SCHMIDT, W., J. ROJAS, D. BÖNING, H. BERNAL, S. GARCIA, and O. GARCIA. Plasma-electrolytes in natives to hypoxia after marathon races at different altitudes.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1406–1413, 1999.Purpose:It is well known that altitude natives differ from sea level natives in aspects of fluid and electrolyte homeostasis.Methods:To evaluate exercise and environmental influences on the electrolyte and water status in hypoxia adapted subjects, we investigated 11 well-trained marathon runners (33.7 ± 0.7 yr, 60.5 ± 1.9 kg), native to an altitude above 2600 m, before and after two marathon races. One competition was held at moderate altitude (AM, 2650 m, 14°C, 55% RH, running time 3 h 6 min ± 22 min) and another under tropical conditions (HM, 470 m, 28°C, 70% RH, running time 2 h 54 min ± 30 min). Blood samples were taken 3 d before, immediately after, 1 h after, and 24 h after the races.Results:The loss in body fluid was calculated to be 2.15 L during AM and 5.05 L during HM, respectively. It was compensated mostly by ingested fluids without electrolyte content and by metabolically produced water, which led to hyponatremia during AM (plasma [Na+] from 144.3 ± 0.7 to 131.7 ± 2.1 mmol·L−1). Severe dehydration without significant changes in plasma [Na+] could be detected after HM. Serum antidiuretic hormone concentrations and serum aldosterone concentrations significantly increased during both races and remained at a high level for at least 1 h after both competitions. Serum atrial natriuretic peptide (ANP) concentrations were at a high level at rest, increasing during HM, and decreasing during AM.Conclusion:Under tropical conditions, we found a severe state of dehydration characterized by an extended ANP-response, which was not prevented by water intake during the race. Under hypoxic conditions, however, we found that hyponatremia had developed. This can be partly explained by pure water intake and metabolically produced water, and also, possibly, by a special hypoxia-induced effect.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

LUCÍA, A., L. SERRATOSA, A. SABORIDO, J. PARDO, A. BORAITA, M. MORÁN, F. BANDRÉS, A. MEGÍAS, and J. L. CHICHARRO. Short-term effects of marathon running: no evidence of cardiac dysfunction.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1414–1421, 1999.Purpose:The purpose of this study was to analyze the short-term effects of a marathon race (Madrid Marathon) on both markers of cardiac damage and echocardiographic parameters in a group of 22 runners (17 male and 5 female; 34 ± 5 yr; &OV0312;O2max: 55.7 ± 9.1 mL·kg−1·min−1) with a wide range of fitness levels.Methods:Venous blood samples were collected from each subject 48 h before the race, at race finish, and 6, 24, and 48 h postexercise for the determination of myoglobin, total creatine kinase catalytic activity (total CK), mass concentration of creatine kinase isoenzyme MB (CK-MB mass), and cardiac isoforms of troponin T and I (TnT-c and TnI-c, respectively). In addition, echocardiographic parameters (M-mode two-dimensional and Doppler analysis) indicative of both left ventricular (LV) systolic and diastolic function were obtained three times from each runner: 2–5 d before the race, at race finish, and 24–36 h after exercise.Results:Except in one subject, levels of TnT-c and TnI-c were within normal limits (<0.1 ng·mL−1) in all the samples collected before or after the race. Overall LV systolic function was not altered by marathon running. Finally, LV diastolic function was transiently altered after the race since the ratio between peak early and late transmitral filling velocities (E/A) was significantly reduced at race finish (P< 0.01) and returned to resting levels after 24–36 h.Conclusions:Our findings suggest that marathon running does not adversely affect the hearts of healthy individuals independently from their training status.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

HUE, O., D. LE GALLAIS, A. BOUSSANA, D. CHOLLET, and C. PREFAUT. Ventilatory responses during experimental cycle-run transition in triathletes.Med. Sci. Sports Exerc.,Vol. 31, No. 10, pp. 1422–1428, 1999.Purpose and Methods:To determine the effects of cycling on a subsequent triathlon run, nine male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 5 km of running (C-R), and 4) 30 min of running followed by 5 km of running (R-R). Before and 10 min after the third and fourth trials, the triathletes underwent pulmonary function testing including spirometry and diffusing capacity testing for carbon monoxide (DLCO). During the C-R and R-R trials, arterialized blood samples were obtained to measure arterial oxygen pressure (PaO2). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system.Results:The results showed that 1) the oxygen uptake (&OV0312;O2) observed during subsequent running was similar for the C-R and R-R trials; 2) the ventilatory response (&OV0312;E) during the first 8 min of subsequent running was significantly greater in the C-R than in R-R trial (P< 0.05); 3) only the C-R trial induced a significant increase (P< 0.05) in residual volume (RV), functional residual capacity (FRC), and the ratio of residual volume to total lung capacity (RV/TLC); and 4) although a significant decrease (P< 0.05) in DLCOwas noted after C-R, no difference between the two exercise trials was found for the maximal drop in PaO2.Conclusions:We concluded that 1) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle fatigue and/or exercise-induced hypoxemia, and 2) the greater &OV0312;Eobserved during the first minute of running after cycling was due to the specificity of cycling. This reinforces the necessity for triathletes to practice multi-trial training to stimulate the physiological responses experienced during the swim-cycle and the cycle-run transitions.

ISSN:0195-9131    

出版商:OVID    

年代:1999

数据来源: OVID