Motor abundance and control structure in the golf swing.

Variability and control structure are under-represented areas of golf swing research. This study investigated the use of the abundant degrees of freedom in the golf swing of high and intermediate skilled golfers using uncontrolled manifold (UCM) analysis. The variance parallel to (VUCM) and orthogonal to (VOrth) the UCM with respect to the orientation and location of the clubhead were calculated. The higher skilled golfers had proportionally higher values of VUCM than lower skilled players for all measured outcome variables. Motor synergy was found in the control of the orientation of the clubhead and the combined outcome variables but not for clubhead location. Clubhead location variance zeroed-in on impact as has been previously shown, whereas clubhead orientation variance increased near impact. Both skill levels increased their control over the clubhead location leading up to impact, with more control exerted over the clubhead orientation in the early downswing. The results suggest that to achieve higher skill levels in golf may not lie simply in optimal technique, but may lie more in developing control over the abundant degrees of freedom in the body.

Dynamic stretching and golf swing performance.

The aim of the present study was to examine the effect of dynamic stretching, static stretching and no stretching, as part of a general warm-up, on golf swing performance with a five-iron. Measures of performance were taken 0 min, 5 min, 15 min and 30 min after stretching. Dynamic stretching produced significantly greater club head speeds than both static stretching (Delta=1.9m.s (-1); p=0.000) and no stretching (Delta=1.7 m.s (-1); p=0.000), and greater ball speeds than both static stretching (Delta=3.5m.s (-1); p=0.003) and no stretching (Delta=3.3m.s (-1); p=0.001). Dynamic stretching produced significantly straighter swing-paths than both static stretching (Delta=-0.61 degrees , p=0.000) and no stretching (Delta=-0.72 degrees , p=0.01). Dynamic stretching also produced more central impact points than the static stretch (Delta=0.7 cm, p=0.001). For the club face angle, there was no effect of either stretch or time. For all of the variables measured, there was no significant difference between the static stretch and no stretch conditions. All of the results were unaffected by the time of measurement after stretching. The results indicate that dynamic stretching should be used as part of a general warm-up in golf.

Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility.

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors.

The effect of prosthetic torsional stiffness on the golf swing kinematics of a left and a right-sided trans-tibial amputee.

The golf swing is a biomechanically complex movement requiring three-dimensional movements at the ankle joint complex (AJC), the hips and shoulders. Trans-tibial amputees lose the natural AJC movements as many prostheses do not allow three dimensional foot movements. Torsion devices have been developed and incorporated into prostheses to facilitate internal and external transverse plane rotations. These devices can help amputees to compensate for the loss of movement and to reduce shearing stresses at the stump-socket interface. The primary aim of the present study was to investigate the effects of three torsion devices on body rotations during the golf swing. Two trans-tibial amputees (one right-sided and one left-sided) were analysed using three-dimensional video analysis at address (ADR), the top of the backswing (TBS) and at the end of the follow-through (EFT). The participants played shots with a 3-wood under three different prosthetic conditions (two with a torsion device set to different stiffness values, and one with no torsion device). The results showed that the torsion device served to improve the hip and shoulder rotations of the left-side amputee without increasing perceived stress at the stump. The torsion device had minimal effect on the hip and shoulder rotations of the right-side amputee, although perceived stress was reduced. The difference in results between the right-sided and left-sided amputees was due to the different requirements of each foot during the golf swing. The main problem faced by the right-side amputee was a loss of the sagittal plane movement of ankle joint plantarflexion at EFT, rather than the transverse plane movement.

Trans-tibial amputee gait adaptations as a result of prosthetic inertial manipulation.

PURPOSE: To establish through gait analysis how changing the mass at the distal end of an in-house, custom-made trans-tibial dynamic elastic response prosthetic limb altered selected gait variables. Including; walking velocity, cadence, single support and hip power for a single amputee. METHOD: A before-after single-subject research design was used with two interventions. A 3-dimensional gait analysis was conducted to analyse the effect on selected gait variables. The mass and moment of inertia of the prosthesis were altered by inserting wedges of different materials. RESULTS: Altering the mass had little effect on the cadence, single support or the velocity. Both the affected and intact limb hip pull-off power at terminal stance was increased, although the effect was greater for the affected limb than for the intact limb. The affected limb hip power at initial contact did not alter in a manner directly related to the mass. CONCLUSIONS: Altering the mass had an inconsistent effect on the gait parameters tested. The subject volunteered that he preferred the prosthesis of the middle mass.

An audit of the effect of intravenous antibiotic treatment on spirometric measures of pulmonary function in cystic fibrosis.

BACKGROUND: This retrospective audit was undertaken to compare the efficacy of home intravenous (i.v.) antibiotic therapy, hospital i.v. antibiotic therapy and a combination of these 2 approaches, as determined by spirometric measures of lung function in cystic fibrosis (CF) patients, each with an acute respiratory exacerbation. METHODS: Pulmonary function, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), forced expiratory flow rate between 25 per cent and 75 per cent of vital capacity (FEF25-75), and peak expiratory flow rate (PEFR) were compared between groups at the beginning and at the end of an IV antibiotic course. RESULTS: Treatment of exacerbations resulted in a significant improvement (p < 0.05) in lung function irrespective of where patients were treated. The percentage improvement in FEV1, FVC, and FEF25-75, were significantly greater in patients treated in hospital compared to those who had home i.v. treatment (p < 0.05). CONCLUSION: Hospital i.v. antibiotic therapy resulted in greater improvements in FEV1, FVC and FEF25-75 than home i.v. antibiotic therapy in CF patients with an acute respiratory infection.

Hip and shoulder rotations during the golf swing of sub-10 handicap players.

The motion of the shoulders, arms and club during the golf swing has often been explained using the 'double pendulum' model. Despite subsequent explanations for the actions of the distal segments of the body, the coordination of more proximal segments during the swing is less well understood. To ascertain the pattern of centre of mass motion and hip and shoulder rotations that result in a high clubhead speed at impact, the swing used in driving from the tee of eight low-handicap golfers was videotaped and analysed using three-dimensional techniques. The shoulders rotated in excess of 90 degrees during the backswing and, in 75% of the golfers, continued rotating away from the flag as the hips began turning back towards it. This sequential pattern of hip and shoulder rotation indicated that they conformed to the 'summation of speed' principle, which is hypothesized to result in a greater torque being applied to the club before impact. The speed of the drive was also benefited by the centre of mass shifting exclusively in the intended direction of ball flight during impact.

The effect of changing the inertia of a trans-tibial dynamic elastic response prosthesis on the kinematics and ground reaction force patterns.

The aim of this study was to assess, by means of gait analysis, the effect on the gait of a trans-tibial amputee of altering the mass and the moment of inertia of a dynamic elastic response prosthesis. One male amputee was analysed for four to five walking trials at normal and fast cadences, using the VICON system of motion analysis and an AMTI force plate. The kinematic variables of cadence, swing time, single support time and joint angles for the knee and hip on the affected and intact sides were analysed. The ground reaction force was also analysed. The sample size was limited to one as an example to indicate the changes which are possible through simply changing the inertial characteristics. Descriptive statistics are used to demonstrate these changes. Three mass conditions for the prosthesis were analysed m1: 1080g; m2: 1080 + 530g; m3: 1080 + 1460g. The m1 condition is the mass of the prosthesis with no added weight while m2 and m3 were attachments of the same geometrical shape but were made from different materials. It was felt that the large mass range would highlight biomechanical adjustments as a result of its alteration. The effect on selected temporal characteristics were that as the speed increased the cadence changed and the affected side single support times as a percentage of the gait cycle were altered. The effect on the joint angles was also apparent at the hip and knee of both sides. The ground reaction force patterns were similar for all three mass conditions, though the impact peak which was evident in the intact limb was missing, indicating a shock absorbing property in the prosthesis. Clearly, changing the mass and moment of inertia has an effect on the kinematic variables of gait and should be considered when designing a prosthesis.

A survey of exercise based cardiac rehabilitation services in Northern Ireland.

A survey was undertaken to establish the extent of provision of phase III exercise-based cardiac rehabilitation in Northern Ireland. Detailed information was obtained on patient referral mechanisms, patient assessment, the exercise component of cardiac rehabilitation and the use of outcome measures. The results suggest that cardiac rehabilitation in Northern Ireland has developed on an ad hoc basis, and although most centres accept myocardial infarction and coronary artery bypass graft patients for cardiac rehabilitation, higher risk patients are generally excluded from these programmes. Currently, little in the way of standard outcome measures are being used to evaluate the effectiveness of existing cardiac rehabilitation services. This paper makes several recommendations to facilitate the development of a more standardised service within Northern Ireland.

Influence of exercise adherence level on modifiable coronary heart disease risk factors and functional-fitness levels in middle-aged men.

The study investigated the potential health benefits of two levels of short-term exercise intervention, compared with non-intervention, on selected modifiable coronary heart disease (CHD) risk factors and functional fitness states in middle-aged men. All subjects underwent medical screening and signed informed consent before carrying out a standardized graded treadmill walk which required exercise up to 85% of age-predicted maximal heart rate. The results of the test were used together with musculoskeletal fitness assessments, for the prescription of a personalized exercise programme lasting 14 weeks. In all, 55 subjects were classified by adherence into high (HA, n = 20), low (LA, n = 19), or non-adherence (NA, n = 16) groups according to the degree of documented participation in the programme based on standard criteria (American College of Sports Medicine 1978, 1990). In addition, the respective groups of subjects were classified according to other modifiable and non-modifiable CHD risk factors and compared by self-reported levels of activity and sport involvement as well as perceived body weight classification. The results indicated that there were more comprehensive improvements in functional fitness including significant gains in aerobic endurance capacity, muscular endurance and flexibility in the HA group compared with the LA and NA groups. However, there was little or no change in the modifiable CHD risk factors in any of the respective groups, although anthropometric indices of weight, body mass index (BMI), skinfolds and waist:hips ratio tended to decrease in the HA and LA groups but increased marginally in the NA group.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise respiratory pattern in elite cyclists and sedentary subjects.

We investigated the breath-by-breath pattern of ventilatory response to bicycle exercise in seven elite male cyclists (VO2max = 71.7 ml X min-1 X kg-1) and ten sedentary males (VO2max = 47.3 ml X min-1 X kg-1) to analyze differences in breathing patterns between individuals with normal and high exercise ventilations (VE). The mean VEmax of the athletes (ATH) exceeded that of the sedentary subjects (SED) by 34.6% (183 vs 136 l X min-1) and was proportional to the difference in VCO2max between the groups (5.9 vs 4.23 l X min-1). The ATH used an average of 89% of their 15-s maximum voluntary ventilation (MVV) during maximum exercise while SED used only 71%. The ATH had slightly, but not significantly, larger vital capacity (FVC). Both groups used about half of their FVC at maximum tidal volume (VT), VT was 47% and 49% of FVC in ATH and SED, respectively. The ATH achieved the higher VEmax by achieving a greater increase in respiratory frequency (63/min vs 49/min), which was accomplished by significant decreases in both inspiratory (T1) and, more importantly, expiratory (TE) time. There was a tendency for athletes to have a somewhat more regular breathing pattern. Both 1/T1 and mean inspiratory flow (VT/T1) were highly correlated with VE, but there were no differences in these relationships between ATH and SED. Highly-conditioned athletes, therefore, respond to the increased demand for CO2 elimination by utilizing a higher respiratory frequency achieved through a reduction of both inspiratory and expiratory duration, but not by utilizing a larger tidal volume (i.e., as percent FVC) than less fit individuals.