摘要:

Throwing injuries of the shoulder can result from an acute traumatic event or chronic overuse. Shoulder impingement has multiple etiologies; the most common being rotator cuff weakness/overuse and resultant glenohumeral instability. However, an uncommon cause of shoulder impingement syndrome is that of a nonnfused os acromiale. There are three centers of ossification in the acromion which are usually completely fused by 18 yr of age. The most common site of nonunion is between the meso-acromion and meta-acromion. Os acromiale is reported at a rate of 14/1000 (1.4%) and is bilateral in approximately 62% of cases. The classic diagnosis is radiographically defined with both AP and axillary lateral views, and a contralateral comparison view may be helpful. Computerized axial tomography also aids in the diagnosis. Most os acromiale are asymptomatic. However, if recalcitrant impingement syndrome and/or rotator cuff tears are found in association with os acromiale, then surgical fusion or resection of the ossicle is recommended.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

This study reviewed the assessment of medial tibial stress syndrome (MTSS), a common lower limb overuse injury among athletes and dancers. The purpose of the study was twofold: 1) to determine whether abnormal foot alignment is positively correlated with a previous diagnosis of MTSS and 2) to assess the interrater reliability of the proposed methods. We therefore studied foot alignment retrospectively both qualitatively and quantitatively in both a closed and open kinetic chain manner. The specific measures evaluated were: 1) standing foot angle (SFA), 2) nonweight-bearing hindfoot angle, and 3) nonweight-bearing forefoot angle. Qualitative parameters were used for the non weight-bearing measures along the continuum: varus-neutral-valgus. The authors made their measurements independently and were blinded to the previous authors results. Case limbs (as defined as the symptomatic limb in a subject with the diagnosis of MTSS) were found to have a SFA < controls (P= 0.0001). Case limbs also tended towards having a higher incidence of hindfoot (P= 0.017) as well as forefoot (P= 0.08) varus alignment. We found that a SFA of <140° and a varus alignment of the hindfoot and/or forefoot, were predictive of a previous history of MTSS. These methods were found to be reliable and can be performed in an office setting without any special equipment.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

It has been postulated that coactivation of antagonist hamstring musculature during active knee extension aids the anterior cruciate ligament (ACL) in maintaining joint stability by exerting an opposing torque to anterior tibial displacement induced by the quadriceps. It was the purpose of this study to compare contralateral patterns of hamstring coactivation in subjects who have suffered ACL dysfunction with subjects who have normal knees. Five subjects who had suffered ACL dysfunction (INJ) and five uninjured (UNI) subjects performed maximal flexions and extensions of the knee on a modified isokinetic dynamometer at 100° and 300°·s−1. Simultaneous recordings of torque, angular displacement, and electromyographic (EMG) activity from the hamstring musculature were computer processed. No significant differences (P< 0.05) in torque were found between ACL/normal and right/left limbs for the INJ and UNI groups, respectively. For the INJ subjects, mean coactivation of the normal limb hamstrings during extension averaged twice that of the ACL limb. In contrast, no significant difference was found for the same comparison between right and left limbs in the UNI group. The results of this study suggest that asymmetry in hamstring coactivation during knee extension may result from ACL dysfunction.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The purpose of the study was to 1) determine the effects of a low-volume resistive exercise protocol on serum concentrations of estradiol (E2), progesterone (P4), growth hormone (GH), testosterone (T), and androstenedione (AN) and 2) ascertain whether the endocrine responses are affected by the phase of the menstrual cycle. Eleven untrained, healthy women were assigned to either an early follicular or luteal testing group. The subjects completed three sets of bench press, lat-pull, leg extension, and leg curl exercises at a 10 repetition maximum load on fixed machines with 2-min of rest between sets. Blood samples were collected through an indwelling cannula before, during, and after the exercise. Area-under-the-response-curve (AUC) data demonstrated that E2concentrations were significantly elevated in both follicular and luteal phases with a greater response in the luteal phase. Moreover, data suggest there is a luteal phase-induced increase in GH and AN in response to the low-volume resistive exercise; however, P4and T concentrations in untrained women are not increased by low-volume resistive exercise with 2-min rest periods, nor does the altered hormonal milieu produced by the phase of the menstrual cycle affect these hormonal responses.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The objective of this study was to determine predictors of left ventricular mass (LVM) and resting systolic blood pressure (SBP) in preteenage children. Subjects consisted of 124 children (7.9–12 yr) from Masculine, Iowa. Methods consisted of echocardiographic examinations, random-zero SBP, hormone determination of scrum androgens, physician's examination for Tanner stage, anthropometry, maximal bicycle ergometry, hand grip dynamometry, and a physical activity survey. Least square's regression analysis quantified the percentage of explained variability in LVM and resting SBP attributable to the predictor variables. All models were adjusted for body composition. In boys, 72% of the variability in LVM was explained by fat-free body mass (FFM), sum of skinfolds, and peak SBP. In girls, FFM and peak SBP explained 69% of the variability in LVM. Peak SBP was also a significant predictor of resting SBP in boys and girls. Study results indicated that physical fitness and physical activity are not significant predictors of LVM nor resting SBP; however, after adjusting for body composition, peak SBP was an independent predictor of LVM and resting SBP. This result suggests that peak SBP may aid in the prediction of subsequent hypertension and its complications such as left ventricular hypertrophy.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Injuries that required physical or medical assistance were recorded for participants at the United States Tennis Association National Boys' Tennis Championships from 1986–1988, 1990–1992 (N= 1440, 240 athletes per year). Over the 6-yr period, a total of 304 athletes (or 21.1%) sustained new or recurrent injuries that required evaluation by the medical team. New injuries alone numbered 145 (incidence rate of 9.9 per 100 athletes). The analysis of injuries showed a higher rate of lower than upper extremity injuries. When evaluated by anatomic regions, back injuries were most common followed by thigh, shoulder, and ankle injuries, respectively. When evaluated by injury type, strains and sprains were most common (71% of all injuries) with fractures and dislocations being rare (1.3% of all injuries). The lower extremity provided the majority of sprain type injuries with 87.5% of ligament sprains coming from the knee and ankle. Injuries with tennis eponyms (i.e., tennis toe, tennis leg, tennis elbow, and tennis shoulder) were rare (0%–5% of all injuries). It would appear that these young elite athletes are at significant risk of injury.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Calcium, magnesium, phosphorus, and iron are important to a wide variety of body functions, such as mineralization of bones, serving as cofactors to many enzyme systems, sustaining muscle and nerve excitation, and, in the case of iron, maintaining the oxygen carrying capacity of the blood. Many female athletes consume less calcium than the recommended dietary allowance (RDA). This is of concern because of the need to achieve peak bone mass during adolescence and the possible relationship of poor calcium intake to stress fractures. Athletes appear to have adequate magnesium and phosphorus status. However, those athletes who are on calorie-restricted diets may not be ingesting sufficient quantities of magnesium and possibly phosphorus. Limited data have suggested that magnesium status is indirectly related to strength improvement as well as the incidence of muscle cramps. Acute ingestion of phosphorus (phosphate loading) has been shown to improve aerobic capacity. Iron depletion is common in female athletes but similar to the general population. Iron supplements are of health benefit, but of questionable performance benefit, to those who are iron depleted and nonanemic. To maintain optimal status of these minerals, it is recommended that nutrient rich foods be ingested including dairy products and foods high in heme iron.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Different intrinsic properties of the constituent cells of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) have been proposed to be one of the factors in the differential repair mechanisms. We have found that the outgrowth of cells from rabbit ACL explants was slower than from MCL explants after 10 d. Growth curves of ACL and MCL cultures at both Passage numbers 2 and 6 showed a slower rate of proliferation of ACL cells than MCL cells (P< 0.005). The proliferative response of rabbit ACL and MCL cells to b-FGF and TGF-β was also investigated. Both b-FGF and TGF-β had no significant effect on cell proliferation of ACL and MCL cultures after 48 h. However, TGF-β did have an inhibitory effect on thymidine incorporation, especially at concentrations greater than I ng·ml−1, while b-FGF stimulated thymidine incorporation in ACL and MCL in a dose-dependent manner. Differences in the cell morphology of the ACL and MCL cells grown in culture were seen also. Cells from Passages 3–6 demonstrated these differences more prominently, and phalloidin staining for actin showed that ACL cells appeared to have more intracellular actin fibers.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

We sought to determine whether exercise intensities not elevating blood lactate produce alterations in physiological responses to exercise associated with training. Twenty-seven sedentary young men performed five cycle ergometer training sessions·wk−1for 5 wk. Training power outputs were randomized to power outputs corresponding to either 80% of the lactic acidosis threshold (LAT), 25%Δ or 50%Δ (where Δ is the difference between LAT and peak &OV0312;O2power outputs estimated from incremental exercise tests). Exercise sessions were 30 min for the 50%Δ group and were proportionately longer for other groups, so that total work did not vary among groups. Before and after training, subjects exercised for 15 min (or to tolerance) at pretraining 80% LAT, 25%Δ, 50%Δ, and 75%Δ power outputs. Continuous O2uptake, CO2output, ventilation and heart rate, and end-exercise blood lactate, norepinephrine, and epinephrine were measured. For the 80% LAT group, posttraining end-exercise values for the 75%Δ test were significantly lower for each of these variables. There were similar reductions in each variable in all three training groups; no significant differences among groups were seen. Thus, in healthy subjects exercise which does not elevate blood lactate alters constant power output responses as effectively as exercise which elevates lactate, provided that total training work is the same.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Anaerobic threshold, also termed 4.0 mmol·l−1threshold (AT4), and individual anaerobic threshold (IAT), presumably indicate the workload corresponding to maximal factate steady state (MLSS) during an incremental workload test. MLSS is the highest blood lactate concentration (BLC) resulting in a steady state during constant workload. The purpose of the present investigation was to ascertain the validity of AT4 and IAT as related to MLSS during rowing ergometry. Nine rowers (mean ± SD age 20.2 ± 1.6 yr; HT 187.2 ± 4.9 cm; WT81.1 ± 6.3 kg) performed an incremental load test to determine AT4, IAT and maximal workload and several 30 min constant workloads for MLSS measurement on a mechanical rowing ergometer. The incremental load test was conducted at 215 W and increased by 35 W every 3.0 min. The first 30 min constant workload was conducted at 60% of maximal workload (363.3 ± 45.1 W). If a constant load test resulted in a steady state of BLC subsequent constant load tests were performed and workload increased by 3% to 10% after each constant load test until no steady state of BLC could be observed. AT4 (287.0 ± 20.5 W), IAT (287.1 ± 25.1 W), and BLC at IAT (4.2 ± 0.8 mmol·l−1) were higher (P< 0.001) compared to MLSS workload (255.1 ± 17.5 W) and MLSS (3.0 ± 0.6 mmol·l−1), respectively. Independent of the practical application of AT4 and IAT, in rowing AT4 and IAT do not represent MLSS workload.

ISSN:0195-9131    

出版商:OVID    

年代:1995

数据来源: OVID