Examining the validity of the drinking motives questionnaire for identifying reward and relief drinking subgroups in college students.

BACKGROUND: Heavy alcohol use in college is associated with a risk of developing alcohol use disorder. Characterizing variability in individual risk factors for alcohol use could help mitigate risk by informing personalized approaches to prevention. This study examined the validity of a brief measure for identifying reward/relief drinking phenotypes in non-treatment-seeking young adults. METHODS: College students (n = 454) who reported binge drinking completed the Drinking Motives Questionnaire-Revised-Short Form (DMQ-R-SF). Confirmatory factor and latent profile analyses (CFA; LPA) of the DMQ-R-SF were performed to assess structural validity and identify reward/relief drinking subgroups. We compared models measuring reward drinking with the DMQ-R-SF enhancement motives (reward-enhancement) subscale to models measuring reward drinking with enhancement and social motives (reward-enhancement/social). Across models, relief drinking was measured with coping motives. We examined associations between reward/relief drinking subgroups and alcohol and personality variables concurrently and prospectively at a 6-week follow-up. RESULTS: A two-factor reward and relief structure of the DMQ-R-SF was supported. Three latent profiles were identified (low reward/low relief: n = 133, high reward/low relief: n = 249; high reward/high relief: n = 72). Both CFA and LPA models that utilized reward-enhancement/social items indicated a better fit than reward-enhancement items alone. At baseline, individuals in the high-reward/high-relief profile demonstrated the poorest alcohol use outcomes and higher negative affect. Those in the high-reward/low-relief profile demonstrated greater alcohol use severity than those in the low-reward/low-relief profile. Prospectively, individuals classified in the high-reward/low-relief subgroup reported greater binge drinking frequency and those in the high-reward/high-relief profile reported greater alcohol consequences. CONCLUSIONS: The DMQ-R-SF is a valid measure for identifying reward and relief drinking subgroups in college students with binge drinking and could have utility for precision prevention efforts that target individuals in the high-reward/low-relief and high-reward/high-relief subgroups.

A 5-week whole body vibration training improves peak torque performance but has no effect on stretch reflex in healthy adults: a randomized controlled trial.

AIM: This study aimed to investigate the neuromuscular adaptation following a 5-week high frequency and low amplitude whole body vibration (WBV) exercise training. METHODS: The study is a prospective, double blind, randomized controlled intervention design with a total of 19 subjects volunteered to participate in the study. They were randomly assigned either to WBV exercise training or control group. Both groups participated in a 5-week training program. The intervention group received WBV in semi-squat position on a device with an amplitude of 0.76 mm, frequency of 40Hz, and peak acceleration of 23.9 m/s2. Each vibration training session consisted of 6 series of 60s on with 30s rest period in between. The control group underwent the same statically mini-squatting position without exposure to WBV. The effectiveness of the vibration program was evaluated by vertical jump test and the isokinetic knee extensor peak torque. The possible neural factors that contributed to the improved muscular performance were evaluated by the stretch induced knee jerk reflex. RESULTS: WBV training significantly enhanced the isokinetic knee extensor peak torque performance. Two-way mixed repeated measures analysis of variance revealed significant time effect of the changes in the peak torque (P=0.043) and the effect was significantly different between the intervention and control group (P=0.042). WBV did not affect vertical jump height, reflex latency of VL, EMGVL, and knee jerk angle. CONCLUSION: The results of this study do not support the hypothesis that the improvement in the muscular performance when subjects exposed to WBV training is attributed by neuromuscular efficiency via modulation of the muscle spindle sensitivity.

A prospective cohort study of hamstring injuries in competitive sprinters: preseason muscle imbalance as a possible risk factor.

BACKGROUND: Hamstring injuries are common in sprinters. Identifying preseason risk factors is essential to target injury-prone athletes and develop injury preventive measures. OBJECTIVE: To investigate the incidence of hamstring muscle injury in sprinters over an athletic season and to explore the preseason predictor of this injury. DESIGN: Prospective cohort study. PARTICIPANTS: 44 sprinters from the Hong Kong Sports Institute, the Hong Kong Amateur Athletic Association and intercollegiate athletic teams were recruited. METHODS: Preseason assessment of hamstring flexibility, concentric and eccentric isokinetic peak torque and peak torque angle were obtained at the beginning of an athletic season. The athletes were followed over 12 months and were asked to report all injuries resulting from training and competition. RESULTS: Eight athletes sustained hamstring injuries over the season. The injury rate was 0.87 per 1000 h of exposure. The incidence of injuries was higher at the beginning of the season, with 58.3% injuries occurring in the first 100 h of exposure. Cox regression analysis revealed that athletes with a decrease in the hamstring : quadriceps peak torque ratio of less than 0.60 at an angular velocity of 180 degrees/s have a 17-fold increased risk of hamstring injury. CONCLUSION: Performing preseason hamstring : quadriceps peak torque ratio assessments may be useful to identify sprinters susceptible to hamstring injury.

Shift of peak torque angle after eccentric exercise.

This study aims to investigate the changes in the mechanical properties of quadriceps muscle following a sub-maximal concentric-eccentric stepping exercise protocol. Twenty-four untrained healthy subjects aged 21.9 +/- 0.55 years were asked to perform a 10-minute stepping exercise where the dominant leg worked eccentrically and the non-dominant leg worked concentrically at a rate of 15 cycles/min. The quadriceps isokinetic peak torque and the corresponding peak torque angle at angular velocity of 60 degrees /sec, and muscle soreness were determined at baseline, immediately after, day 1 and day 2 after the exercise protocol. Repeated measures of ANOVA showed no change in the peak torque after the eccentric exercise and concentric exercise (p > 0.05). There was a significant shift in the peak torque angle to longer muscle lengths in the eccentrically-exercised leg immediately (65.6 +/- 2.21 degrees ) and on the following two days after exercise (day 1: 68.3 +/- 2.71 degrees ; day 2: 67.4 +/- 2.51 degrees ) when compared with baseline (61.4 +/- 1.55 degrees , p < 0.05). These features were not observed in the concentrically-exercised leg. Eccentric exercise produced a higher level of soreness than concentric exercise at day 1 and 2 after the protocol. Submaximal eccentric exercise could bring about changes in the muscle properties resulting in a shift in the angle-torque relationship to longer muscle length without significant force deficit.

The 100-km ultradistance race in Hong Kong: physical fitness profile and team performance outcomes.

AIM: The aim of this study was to determine different variables leading to a successful completion of a 100-km ultradistance team event. METHODS: Regular physical activity patterns, self-perceptions of fitness level and physical fitness profile were determined in subjects (n=253) registered for Trailwalker 2000. The battery of fitness tests included cardiopulmonary fitness, flexibility, muscular strength, muscular endurance and body fat composition. RESULTS: The physical fitness data reveals that the subjects in this study have an above average fitness level compared with the norm. There was association of self-perceived fitness with physical fitness parameters (P=0) and significant correlation of the total fitness score with the completion time (P=0.02). More importantly, the team member with the lowest fitness total score was correlated with the finish time at the event (P=0). Logistic regression model identified that total fitness score and years of experience in Trailwalker were predictive of a successful completion in the event (r=0.37; P=0.007). However, the low variance suggested that the selected physical fitness tests have low prediction sensitivity to characterize the specific population in the study. CONCLUSIONS: There is a strong need to determine a combination of physical fitness tests that could accurately predict the performance of participants in the Trailwalker event.

Mechanisms of stretch-induced muscle damage in normal and dystrophic muscle: role of ionic changes.

Muscle damage, characterized by prolonged weakness and delayed onset of stiffness and soreness, is common following contractions in which the muscles are stretched. Stretch-induced damage of this sort is more pronounced in the muscular dystrophies and the profound muscle damage observed in these conditions may involve similar pathways. It has been known for many years that damaged muscles accumulate calcium and that elevating calcium in normal muscles simulates many aspects of muscle damage. The changes in intracellular calcium, sodium and pH following stretched contractions are reviewed and the various pathways which have been proposed to allow ion entry are discussed. One possibility is that TRPC1 (transient receptor potential, canonical), a protein which seems to form both a stretch-activated channel and a store-operated channel, is the main source of Ca(2+) entry. The mechanisms by which the changes in intracellular ions contribute to reduced force production, to increased protein breakdown and to increased membrane permeability are considered. A hypothetical scheme for muscle damage which incorporates these ideas is presented.

Relationships of perceived benefits and barriers to physical activity, physical activity participation and physical fitness in Hong Kong female adolescents.

AIM: Previous studies that examined participation in physical activity suggested that female adolescents were less active compared with males. However, the relationship between physical fitness, physical activity participation, and perceived benefits and barriers for physical activity to adolescents, irrespective of gender, has not been made clear. This study examines the association of these factors in female adolescents. METHODS: Physical activity participation and perceived benefits and barriers to physical activity were determined in 206 secondary school female subjects (aged 11 to 18) using a validated questionnaire. RESULTS: Subjects with a correct concept about optimal physical activity participation to maintain health engaged in an activity level higher than the group without a correct concept (t=2.37, p=0.02). A significant correlation was established between the physical activity participation with "health" (r=0.22, p<0.001) and "body image" (r=0.17, p=0.02) in the perceived benefit category. The individual factor, "make me feel better in general" in the "health" category (p=0.04) and the intention to participate (p<0.001) were shown to be significant predictors for physical activity participation. The combined effects of the regression model explained 35.9% of the variance in participation in physical activity. CONCLUSION: Policies to support regular physical activity participation at school and out-of-school should be strategically developed and promoted, highlighting the promotion of health benefits in exercise and the reinforcement of initial intent towards exercise.

Effect of eccentric contraction-induced injury on force and intracellular pH in rat skeletal muscles.

The effect of eccentric contraction on force generation and intracellular pH (pH(i)) regulation was investigated in rat soleus muscle. Eccentric muscle damage was induced by stretching muscle bundles by 30% of the optimal length for a series of 10 tetani. After eccentric contractions, there was reduction in force at all stimulation frequencies and a greater reduction in relative force at low-stimulus frequencies. There was also a shift of optimal length to longer lengths. pH(i) was measured with a pH-sensitive probe, 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein AM. pH(i) regulation was studied by inducing an acute acid load with the removal of 20-40 mM ammonium chloride, and the rate of pH(i) recovery was monitored. The acid extrusion rate was obtained by multiplying the rate of pH(i) recovery by the buffering power. The resting pH(i) after eccentric contractions was more acidic, and the rate of recovery from acid load post-eccentric contractions was slower than that from postisometric controls. This is further supported by the slower acid extrusion rate. Amiloride slowed the recovery from an acid load in control experiments. Because the Na(+)/H(+) exchanger is the dominant mechanism for the recovery of pH(i), this suggests that the impairment in the ability of the muscle to regulate pH(i) after eccentric contractions is caused by decreased activity of the Na(+)/H(+) exchanger.

A systematic review of interventions to prevent lower limb soft tissue running injuries.

OBJECTIVES: To assess the available evidence for preventive strategies for lower limb soft tissue injuries caused by running. METHODS: An electronic database search was conducted using The Cochrane Musculoskeletal Injuries Group Specialised Register, The Cochrane Controlled Trials Register, Medline, Embase, Sport Discus, Heracles, Atlantes, Biosis, Cinahl, Scisearch, Current Contents, Index To Theses and Dissertation Abstracts. Any randomised or quasi-randomised trials evaluating interventions to prevent running injuries to lower limb soft tissue were included. The eligibility of trials for inclusion and the quality of the trials were independently assessed by two reviewers. RESULTS: Exposure to a high training load (duration, frequency, or running distance) increases the risk of injury, and thus modification of the training schedule can reduce the incidence of injury. The effectiveness of stretching exercises and of insoles in the prevention of lower extremity soft tissue injuries caused by running is not known. Wearing a knee brace with a patellar support ring may be effective in the prevention of anterior knee pain caused by running. CONCLUSIONS: This review provides evidence for the effectiveness of the modification of training schedules in reducing lower limb soft tissue running injuries. More studies are required to quantify the optimal training loads and to confirm that knee braces can prevent knee pain. It is important to note that the studies included in this review had few female participants therefore the results may not be generalisable.

Interventions for preventing lower limb soft-tissue injuries in runners.

BACKGROUND: Overuse musculoskeletal injuries occur frequently in runners. Suggestions for prevention have focused on stretching exercises, modifying training schedules and the use of protective devices such as braces and insoles. To date, no systematic analysis of the literature on the effectiveness of these strategies in the prevention of overuse injuries has been published. OBJECTIVES: The objective of the review was to evaluate the evidence from randomised controlled trials on the prevention of lower limb soft-tissue running injuries. SEARCH STRATEGY: An electronic database search included The Cochrane Musculoskeletal Injuries Group specialised register (date of last search October 2000), The Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 1999), MEDLINE (from 1966), EMBASE (from 1980), SPORT Discus (1975-2000), HERACLES (1975-2000), ATLANTES (1980-1996), BIOSIS, CINAHL, SCISEARCH, Current Contents, Index To Theses and Dissertation Abstracts. Date of last search for these databses: May 2000. SELECTION CRITERIA: Any randomised or quasi-randomised trials evaluating interventions to prevent lower limb soft-tissue running injuries. DATA COLLECTION AND ANALYSIS: All trials fulfilling the selection criteria were assessed by two reviewers independently. Data were also extracted independently by the two reviewers using a pre-derived data extraction form. Exploratory analyses, including pooling of results from groups of trials of similar designs were undertaken, using a fixed effects model. Results were reported as relative risks (RR) with 95 per cent confidence intervals (95% CI). MAIN RESULTS: Twelve trials with 8,806 participants were included. In one trial, a single control group was matched to three different included intervention groups. The effectiveness of stretching exercises (5 trials, 1944 participants in the intervention groups, 3159 controls), and of insoles and footwear modification (5 trials, 903 participants in the intervention groups, 3006 controls) in the prevention of lower extremity soft tissue injuries associated with running is unknown. Reducing the distance, frequency and duration of running may be effective in the prevention of lower extremity soft tissue injuries associated with running (3 trials, 514 participants in intervention groups, 1663 controls). Wearing a knee brace with a patellar support ring may be effective in the prevention of running-associated anterior knee pain (1 trial, 27 participants in the intervention group, 33 controls). REVIEWER'S CONCLUSIONS: This review provides some evidence for the effectiveness of the modification of training schedules, but there is insufficient evidence to determine the effectiveness of stretching exercises for major lower limb muscle groups in reducing lower limb soft-tissue running injuries. More studies are required to confirm that knee braces may prevent knee pain, to clarify the role of stretching, and to quantify optimal training loads. Generalisability of the results may be limited by the intensive nature of military training (the context for most of the studies) and the inclusion of only small numbers of women.

Marathon finishers and non-finishers characteristics. A preamble to success.

BACKGROUND: To investigate if the characteristics and training profiles of runners are significant indicators to predict a successful completion of a marathon. EXPERIMENTAL DESIGN: comparative investigation between two groups of runners at a marathon race. SETTING: participants of the study came from the 1998 Standard Chartered New Airport International Marathon in Hong Kong. PARTICIPANTS: 113 runners were investigated, of which 58 runners dropped out at the first 10 km of the race, while the other 55 were those that consulted for physiotherapy service after the marathon. MEASURES: using questionnaire, the characteristics and the training profiles of these runners were obtained. These included weekly training distance, longest and shortest training distance per session in one week; warm-up and stretching exercise with the training sessions, number of marathons previously finished and the runners' opinion of optimal training mileage to complete a marathon. RESULTS: Independent t-tests with Bonferroni adjustment were used to investigate the difference between the two groups, the results showed significant difference in the weekly training distance (p=0.00), longest and shortest training distance per week (p=0.00), and personal opinion on optimal weekly training distance for a marathon (p=0.00). Logistic regression modeling was then employed to determine variables that best predict the likelihood of completing a marathon. CONCLUSIONS: The findings indicate that the non-finishers are poorly prepared and the results also identify that the longest mileage covered per training session is the best predictor for a successful completion of a marathon with an odds of 1.21.

Self-perceived exertion level and objective evaluation of neuromuscular fatigue in a training session of orchestral violin players.

The aim of the study was to investigate the self-perceived exertion level and an objective measurement of muscle fatigue on violin players before and after a training session. Fourteen professional violin players volunteered in this study. Surveillance study was used to investigate the demographic characteristics, instrument playing background, playing habits variables and factors associated with playing-related musculoskeletal complaints (PRMCs). The subjective rating of the training-induced exertion was evaluated by the Borg scale ratings of perceived exertion (RPE). Surface electromyography (EMG) was used to record the fatigue level of the upper trapezius muscles before and after a training session. Medium frequency (MF) of the EMG signals was used to document the fatigue rate of this muscle. Descriptive statistics revealed a 79% prevalence rate of PRMCs with neck and shoulder region accounting for 57.1% of the areas reported. On the self-perceived exertion level associated with the training session, results indicated a significant increase in fatigue level (p = 0.003) after the training session. Regression analysis and paired samples t-tests revealed no significant difference in the slopes of MF on both sides of trapezius muscle, before and after the training sessions. The disparity in the subjective perception with the objective findings indicated that the violinists' self-perceived exertion arises from multiple sources. The high prevalence of PRMCs in this profession warrants further ergonomic investigation of possible work-related risk factors.

The impact of hospice inpatient care on the quality of life of patients terminally ill with cancer.

This study explored the expectations and experiences of patients with terminal cancer in a hospice inpatient environment in an attempt to evaluate their quality of life and the impact of the care and services provided. A total of 52 patients terminally ill with cancer from 11 hospice units in Hong Kong participated in the study. Data were collected from patients by devising a Hospice Care Performance Inventory (HCPI), which was an interview schedule consisting of 25 items. The HCPI was developed after a review of the literature on the quality of life experienced by patients with advanced cancer and the aims of hospice units in Hong Kong. Each item was rated by the patient on a Likert scale in terms of its importance and the perceived effectiveness of the care provided. The study identified six issues in which expectations did not seem to match effectiveness. These issues indicated areas in which improvement could be attempted to enhance the quality of life for the patients. The most important was maximizing self-care and mobility. Two issues were identified in which effectiveness was high and importance to the patient relatively low. One of these issues was pain management, and the other was spiritual care.

Provision of physiotherapy at the Tsing Ma Bridge international marathon and 10 km race in Hong Kong.

This report examines the delivery of sports physiotherapy at the Tsing Ma Bridge marathon and 10 km race in Hong Kong. The incidence, type of injury encountered, and treatment modalities selected are examined. The report also highlights the flexibility required when planning the provision of such a service.

Kibdelins (AAD-609), novel glycopeptide antibiotics. II. Isolation, purification and structure.

A new glycopeptide antibiotic complex was isolated from the fermentation culture of Kibdelosporangium aridum subsp. largum (SK&F AAD-609) by affinity chromatography on a D-alanyl-D-alanine agarose column. This major components of the complex were resolved by preparative reversed-phase HPLC. Mild acid hydrolysis showed that the new antibiotics have the same mannosyl aglycon (2) as the aridicins. FAB mass spectrometry, isoelectric focusing, potentiometric titration and carbohydrate and fatty acid analyses were used to determine the structures of the five major components of the complex. These studies showed that the kibdelins differ from the aridicins only in the oxidation level at the C-6 position of the amino sugar. Kibdelin A (5), B (6), C1 (7), C2 (8) and D (9) are a series of N-acylglucosamine analogs containing saturated straight and branched chain C10-C12 fatty acids whereas, in kibdelin D the fatty acid component is (Z)-4-decenoic acid.