Islay M. McEwan

Neuromuscular and balance responses to flywheel inertial versus weight training in older persons

AIM Loss of muscle strength and balance are main characteristics of physical frailty in old age. Postural sway is associated with muscle contractile capacity and to the ability of rapidly correcting ankle joint changes. Thus, resistance training would be expected to improve not only strength but also postural balance. METHODS In this study, age-matched older individuals (69.9+/-1.3 years) were randomly assigned to flywheel (n=12), or weight-lifting (n=12) groups, training the knee extensors thrice weekly for 12 weeks. The hypotheses were that owing to a larger eccentric loading of the knee extensors, flywheel training would result in (a) greater gains in quadriceps strength; (b) greater improvements in balance performance compared with weight-lifting training. Isokinetic dynamometry, B-mode ultrasonography, electromyography, percutaneous muscle stimulation and magnetic resonance imaging were employed to acquire the parameters of interest. RESULTS Following training, knee extensors peak isokinetic power increased by 28% (P<0.01) in the flywheel group with no change in the weight-lifting group. Adaptations of the gastrocnemius muscle also occurred in both groups. The gastrocnemius characteristic with the highest response to training was tendon stiffness, with increases of 54% and 136% in the weight-lifting and flywheel groups, respectively (P<0.01). The larger increase in tendon stiffness in the flywheel group was associated with an improvement in postural balance (P<0.01). CONCLUSION Quadriceps flywheel loading not only produces a greater increase in power than weight training but its physiological benefits also transfer/overspill to the plantarflexor muscle-tendon unit resulting in a significantly improved balance. These findings support our initial hypotheses.

Pathoanatomy of posterior ankle impingement in ballet dancers.

Dance is a high performance athletic activity that leads to great numbers of injuries, particularly in the ankle region. One reason for this is the extreme range of ankle motion required of dancers, especially females in classical ballet where the en pointe and demi‐pointe positions are common. These positions of maximal plantar flexion produce excessive force on the posterior ankle and may result in impingement, pain, and disability. Os trigonum and protruding lateral talar process are two common and well‐documented morphological variations associated with posterior ankle impingement in ballet dancers. Other less well‐known conditions, of both bony and soft tissue origins, can also elicit symptoms. This article reviews the anatomical causes of posterior ankle impingement that commonly affect ballet dancers with a view to equipping healthcare professionals for improved effectiveness in diagnosing and treating this pathology in a unique type of athlete. Clin. Anat. 23:613–621, 2010.

Repeatability of stature measurements in individuals with and without chronic low-back pain.

Measurements of reduction in stature have been used to compare spinal loading in chronic low-back pain (CLBP) and asymptomatic populations. Whether there are any differences in the repeatability of stature measurements, between those with and without CLBP, is not known. This investigation aimed to determine the repeatability of stature measurements in those with (n = 12) and without (n = 12) CLBP, and to establish if the ability to produce repeatable measurements is retained after a specific timeframe. Stature measurements were taken on two separate sessions that were 2 weeks apart, using a stadiometer accurate to 0.01 mm. All participants attained a mean SD of ≤0.5 mm by the third measurement set taken on the first session of testing and no significant difference in mean SD was found between those with (0.37 mm) and without (0.40 mm) CLBP (p > 0.05). Intraclass correlation coefficients (ICC) demonstrated good levels of repeatability for all stature measurements obtained from the participants and the values for Standard error of the measurement (SEM) improved as the mean SD decreased with each measurement set. Investigators should have confidence in the ability of those with and without CLBP to produce equally repeatable stature measurements with appropriate prior practice. The second session of testing demonstrated that both groups had retained the ability to achieve the desired level of repeatability (SD ≤0.5 mm) 2 weeks later without further practice.

Diurnal variation in stature: Do those with chronic low-back pain differ from asymptomatic controls?

BACKGROUND Stature loss is a commonly used measure of spinal load. The aim of this study was to investigate the pattern of diurnal stature change in those with and without chronic low-back pain, over a 24-h period. METHODS Eight participants with chronic low-back pain (age 24.6 (SD 4.3) years, height 1.76 (SD 0.08) m, body mass 72.8 (SD 11.1) kg) and eight controls (age 21.8 (SD 2.0) years, height 1.75 (SD 0.10) m, body mass 71.8 (SD 11.6) kg) participated in this investigation. Twenty-four stature measurements were performed over a 24-h period. FINDINGS The trough to peak variation in stature of 17.9 mm (low-back pain group) and 17.6mm (control group) did not differ between groups (P>0.05). Both groups experienced greatest stature change in the 1st hour after rising (31.3% [low-back pain] and 44.6% [control] of total stature change). At approximately 18:00h the LBP group reached a plateau whilst the control group continued to lose stature. Between 14:00 and 18:00h both groups demonstrated a previously unreported recovery of stature. A significant correlation was found between low-back discomfort and stature change in the low-back pain group only. INTERPRETATION No significant difference existed between groups in relation to total stature loss; however the low-back pain group appeared to reach their nadir earlier, possibly exposing other spinal structures to loading for a greater duration. This is supported by the relationship found between stature loss and discomfort. The reversal in stature loss in the afternoon may be of clinical significance and warrants further investigation.

Stature loss and recovery following a period of loading: Effect of time of day and presence or absence of low back pain

BACKGROUND Stature reductions in asymptomatic individuals, caused by a set load, are lower later in the day when stature is in the trough of diurnal variation; hence most stature reduction investigations are conducted in the morning. Recent evidence suggests that it is not the reductions in stature, but the recovery of stature, that is of greatest importance. The aim of this investigation was to establish whether stature recovery is also affected by time of day and to determine if any differences exist between a chronic low back pain and asymptomatic group. METHODS Eleven chronic low back pain participants (age=32.8 SD 7.9 yrs, mass=74.4 SD 14.2 kg and height=1.73 SD 0.07 m) and 11 asymptomatic participants (age=31.0 SD 6.3 yrs, body mass=72.6 SD 11.5 kg and height=1.76 SD 0.09 m) underwent two 20 min loaded walking tasks (10% body mass), one in the morning (09:00) and one in the afternoon (14:00), followed by a 20 min unloaded recovery period. Measurements of stature were obtained throughout. FINDINGS The asymptomatic group experienced significantly less stature reduction (P=0.05; ES=1.1) and greater stature recovery (P=0.02; ES=0.9) in the afternoon compared to the morning. The chronic low back pain group experienced a similar pattern to the asymptomatic group, however no significant difference between sessions for changes in stature was evident P=0.07. INTERPRETATION Further investigations of stature recovery should be restricted to the morning when comparing individuals with and without chronic low back pain, as time of day appeared to have effect on stature recovery, particularly in the asymptomatic group. Time dependent differences in stature change between these two populations warrants further investigation.

The Impact of Increasing Paraspinal Muscle Activity on Stature Recovery in Asymptomatic People

OBJECTIVE To determine whether changes in stature recovery could be exhibited in an asymptomatic group through the use of functional electric stimulation (FES). DESIGN A repeated-measures cohort study considering the effects of FES on stature recovery after a loaded walking task in a group of asymptomatic subjects. Each participant performed the 20-minute loaded walking task (at 10% of body mass) on 2 separate occasions followed by a 20-minute recovery period, once with FES and once without. Measurements of stature using a stadiometer were recorded throughout. SETTING A university laboratory. PARTICIPANTS Eight asymptomatic male volunteers (age, 29.0+/-5.1y; mass, 80.7+/-8.4kg; height, 1.81+/-0.06m) with no history of chronic low back pain (LBP) were recruited through notices in the university and local communities. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Recovery of stature was assessed via stadiometry during the postexercise unloading periods. RESULTS Each participant experienced significantly better stature recovery (percentage of stature reduction) during the control session compared with the FES session, with mean stature recoveries of 104.6%+/-22.9% and 56.3%+/-27.4%, respectively (P=.01). CONCLUSIONS Use of FES correlated with significant reductions in stature recovery. Elevating paraspinal muscle activity may increase compression on the intervertebral disks and therefore diminish the ability to recover the reduction in height caused by the loaded walking task. This investigation offers further support to the theory that the raised paraspinal muscle activity exhibited by persons with chronic LBP leads to reduced stature recovery.

From interprofessional working to transprofessional possibilities: the new age of sports coaching in the United Kingdom

This positional paper is concerned with the professional and occupational interrelationships that coaches are subject to within two areas of UK sports provision. While there are already elements of interprofessional workings within state sponsored elite sports provision, such as the English Institute of Sport, community coaches and sports leaders are now being asked to play an increasing role in sports participation as part of wider social intervention measures. These new occupational positionings are set against a policy backdrop of the on-going professionalization of the UK coaching workforce. Key to the emerging claim to be regarded as a profession is the requirement to be perceived as both partners and equals within the increasingly prevalent discourse surrounding sport, at elite and community levels, as well as the utilization of physical education as a tool of health intervention. We argue that this call for multi-agency working fails to take account of entrenched positioning, the professional siloing of knowledge, and the fear that transgressions across professional boundaries weaken the status and location of groups who may already be subject to notions of professional insecurity. Applying a Bourdieusian lens, this paper proceeds to problematize these emerging relationships and suggest that there needs to be a more considered analysis of their potential impact and possibilities.

When do I get to run on with the magic sponge?: the twin illusions of meritocracy and democracy in the professions of sports medicine and physiotherapy

In this paper, we consider the experiences of healthcare professionals involved in sports medicine in the UK. We are concerned with the inter‐ and intra‐professional relationships found between groups such as medical practitioners and physiotherapists. Drawing on interview data gleaned from doctors, physiotherapists and academics working within sports medicine and education, we provide a Bourdieusian reading of the experiences and professional lives of individuals involved in elite sports medicine provision. Findings suggest that sports medicine practitioners are subject to relationships of power, resistance and compliance. This highlights the shifting landscape of professional emplotments at a time when elite sports medicine in the UK is being foregrounded as a prerequisite to performance excellence.

Omega-3 fatty acids and vitamin D in immobilisation: Part B- modulation of muscle functional, vascular and activation profiles

ObjectivesThis study set out to determine whether two potential protein-sparing modulators (eicosapentaenoic acid and vitamin D) would modulate the anticipated muscle functional and related blood vessels function deleterious effects of immobilisation.DesignThe study used a randomised, double-blind, placebo-controlled design.SettingThe study took part in a laboratory setting.ParticipantsTwenty-four male and female healthy participants, aged 23.0±5.8 years.InterventionThe non-dominant arm was immobilised in a sling for a period of nine waking hours a day over two continuous weeks. Participants were randomly assigned to one of three groups: placebo (n=8, Lecithin, 2400 mg daily), omega-3 (ω-3) fatty acids (n=8, eicosapentaenoic acid (EPA); 1770 mg, and docosahexaenoic acid (DHA); 390 mg, daily) or vitamin D (n=8, 1,000 IU daily).MeasurementsIsometric and isokinetic torque, antagonist muscle co-contraction (activation profile), muscle fatigability indices, and arterial resting blood flow were measured before, at the end of the immobilisation period, and two weeks after re-mobilisation.ResultsMuscle elbow flexion and extension isometric and isokinetic torque decreased significantly with limb immobilisation in the placebo group (P<0.05). Despite no significant effect of supplementation, ω-3 and vitamin D supplementation showed trends (P>0.05) towards attenuating the decreases observed in the placebo group. There was no significant change in muscle fatigue parameters or co-contraction values with immobilisation and no effect of supplementation group (P>0.05). Similarly, this immobilisation model had no impact on the assessed blood flow characteristics. All parameters had returned to baseline values at the re-mobilisation phase of the study.ConclusionOverall, at the current doses, neither ω-3 nor vitamin D supplementation significantly attenuated declines in torque associated with immobilisation. It would appear that muscle function (described here in Part B) might not be as useful a marker of the effectiveness of a supplement against the impact of immobilisation compared to tissue composition changes (described in Part A).

Reliability of a new supination resistance measurement device and validation of the manual supination resistance test.

BACKGROUND Kinematic observations are inconsistent in predicting lower-extremity injury risk, and research suggests that kinetic variables may be more important in this regard. Before kinetics can be prospectively investigated, we need reliable ways of measuring them clinically. A measurement instrument was manufactured that closely mirrors a manual test used to clinically estimate supination resistance force. The reliability of the instrument and the validity of the clinical test were investigated. METHODS The left feet of 26 healthy individuals (17 men and 9 women; mean ± SD age, 25.9 ± 9.2 years; mean ± SD weight, 77.7 ± 13.3 kg) were assessed. Foot Posture Index (FPI-6), manual supination resistance, and machine supination resistance were measured. Intrarater and interrater reliability of all of the measurements were calculated. Correlations of the supination resistance measured by the device with FPI-6, the manual supination resistance test, and body weight were investigated. RESULTS Interrater reliability of all of the measurements was generally poor. The supination resistance machine correlated highly with the manual supination test for the rater experienced with its use. Supination resistance measurements correlated poorly with the FPI-6 and weakly with body weight. CONCLUSIONS The supination resistance machine was shown to have sufficient limits of agreement for the study, but improvements need to be made for more meaningful research going forward. In this study, the force required to supinate a foot was independent of its posture, and approximately 12% of it was explained by body weight. Further work is required with a much larger sample size to build regression models that sufficiently predict supination resistance force and that will be of clinical use. The manual supination test is a valid clinical test for clinicians experienced in its use.