Biomedical subjects

K L Bennell

Publications and source records attributed to K L Bennell.

At least 19 recordsLinked to original sources

PubMed2006

Balance impairment is related to vertebral fracture rather than thoracic kyphosis in individuals with osteoporosis.

INTRODUCTION: Balance impairments have been identified in people with osteoporosis. Although an association between thoracic kyphosis and impaired balance has been reported, the specific role of vertebral fractures has not been considered. This study aimed to investigate the independent effects of osteoporotic vertebral fracture and thoracic kyphosis on balance characteristics in an osteoporotic population. METHODS: Twenty-two individuals with osteoporosis were divided into groups with (n=10) and without (n=12) radiologically diagnosed fracture, and into groups with low (n=11) and high (n=11) thoracic kyphosis. Force-plate-derived balance parameters were recorded during three static standing tasks of 70-s duration. Balance measures were compared between fracture and kyphosis groups, and significant differences were further explored through subgroup analyses, to tease out the relationships between confounded independent variables (fracture and kyphosis) and balance measures. RESULTS: In the anterior-posterior direction, the range and root mean square of shear forces (p=0.048 and p=0.032, respectively), and range of displacement of the centre of pressure (p=0.049) were greater in the fracture group. There were no differences between groups when comparison was based on the magnitude of thoracic kyphosis (all p>or=0.264). Analyses of subgroups supported these findings. DISCUSSION: Vertebral fracture but not thoracic kyphosis is associated with impaired balance characteristics in the osteoporosis population. This finding has important implications for fracture prevention and conservative management regimes.

Aged↗

PubMed2006

Dancing for bone health: a 3-year longitudinal study of bone mineral accrual across puberty in female non-elite dancers and controls.

INTRODUCTION: Weight-bearing exercise during growth enhances peak bone mass. However, the window of opportunity for optimizing positive effects of exercise on peak bone mass remains to be fully defined. Ballet dancing provides a model of mechanical loading patterns required to site-specifically modulate bone. METHODS: We assessed the effects of ballet dancing on bone mineral accrual in female non-elite dancers and normally active controls for 3 years across puberty. We recruited 82 ballet dancers and 61 controls age 8-11 years at baseline. Participants were measured over 3 consecutive years; however, the overlap in ages allowed analysis of the groups across 8-14 years of age. We annually assessed bone mineral content (BMC) at the total body (TB), including upper and lower limb regions, and biannually assessed BMC at the proximal femur and lumbar spine (LS) using dual x-ray absorptiometry (DXA). We derived TB lean mass and fat mass from DXA TB scans. Anthropometry, exercise levels, and calcium intake were also measured biannually. Maturational age was determined by age at peak height velocity (PHV). A multilevel regression model was used to determine the independent effects of body size, body composition, maturation, exercise levels, and calcium intake at each measurement occasion. RESULTS: When adjusted for growth and maturation, dancers had significantly greater BMC at the TB, lower limbs, femoral neck (FN), and LS than controls. Excepting the FN region, these differences became apparent at 1 year post-PHV, or the peripubertal years, and by 2 years post-PHV the differences represented a cumulative advantage in dancers of 0.6-1.3% (p<0.05) greater BMC than controls. At the FN, dancers had 4% (p<0.05) greater BMC than controls in prepuberty and maintained this advantage throughout the pubertal years. CONCLUSIONS: Results from this novel population provide evidence for modest site-specific and maturity-specific effects of mechanical loading on bone.

Adolescent↗

PubMed2006

A pilot randomised controlled trial of eccentric exercise to prevent hamstring injuries in community-level Australian Football.

Hamstring injuries are the most common injury sustained by Australian Football players. Eccentric training has been proposed as a potential preventative strategy. This pilot randomised controlled trial (RCT) evaluated the effectiveness of a pre-season eccentric training program for preventing hamstring injuries at the community level of Australian Football. Seven amateur clubs (n=220 players) were recruited. Players were randomised within clubs to the intervention (eccentric exercise) or control (stretching) groups and randomisation was stratified according to previous history of hamstring injury. Five exercise sessions were completed over a 12-week period, three during the pre-season and two during the first 6 weeks of the season. Compliance was recorded and players were monitored for the season to collect injury and participation data. There was no difference between the control (n=106) or intervention (n=114) groups with respect to baseline characteristics. Only 46.8% of all players completed at least two program sessions. Compliance was poorest for the intervention group. Intention-to-treat analysis suggested that players in the intervention group were not at reduced risk of hamstring injury (RR 1.2, 95% CI: 0.5, 2.8). When only control and intervention group players who participated in at least the first two sessions were analysed, 4.0% of intervention and 13.2% of control group players sustained a hamstring injury (RR 0.3, 95% CI: 0.1, 1.4; p=0.098). The findings suggest that a simple program of eccentric exercise could reduce the incidence of hamstring injuries in Australian Football but widespread implementation of this program is not likely because of poor compliance.

Adolescent↗

PubMed2006

Predictors of hamstring injury at the elite level of Australian football.

BACKGROUND: Hamstring injuries are the most common injury sustained by elite Australian football players and result in substantial costs because of missed training time, unavailability for matches and lost player payments. Evidence to support proposed risk factors for hamstring injury is generally lacking, limiting the development of appropriate prevention strategies. AIM: To identify intrinsic risk factors for hamstring injury at the elite level of Australian football. METHODS: A prospective cohort of 222 players underwent baseline measurement in the form of a self-report questionnaire and a musculo-skeletal screen during the pre-season period of the 2002 Australian football season. Injury surveillance and exposure data were collected for the full season. Logistic regression analyses were used to identify independent predictors of hamstring injury in this group of players. RESULTS: Thirty-one players sustained a hamstring injury. A past history (previous 12 months) of hamstring injury and increasing age were found to be independent predictors of hamstring injury. CONCLUSIONS: Older players and those with a previous history of hamstring injury are target groups for further research and implementation of injury prevention strategies. Restricted ankle dorsiflexion range of movement warrants consideration in the development of prevention programs for hamstring injury.

Adolescent↗

PubMed2006

Patellar taping does not change the amplitude of electromyographic activity of the vasti in a stair stepping task.

OBJECTIVES: To investigate the effect of patellar taping on the amplitude of electromyographic activity (EMG) of vasti activation in subjects with and without patellofemoral pain (PFP). METHODS: Ten participants with PFP and 12 asymptomatic controls were recruited to the study. The study was designed as a randomised crossover trial. Participants completed a stair stepping task. Three experimental conditions were assessed: no tape, therapeutic medially directed tape, and placebo vertically directed tape. The main outcome measure was the EMG amplitude of the vastus medialis obliquus and vastus lateralis during the concentric phase of stair stepping. RESULTS: The application of medially directed therapeutic tape significantly decreased pain in subjects with PFP. However, application of tape over the patella (therapeutic or placebo) did not alter the amplitude of vasti EMG when either the PFP or control participants completed the concentric stair stepping task. CONCLUSION: The results of this study indicate that the positive clinical effects of medially directed therapeutic tape are not due to changes in EMG amplitude of the vasti muscle. Thus other effects such as changes in timing of contraction of the vasti are more likely candidates for the mechanism of efficacy.

Adult↗

PubMed2005

Efficacy of physiotherapy management of knee joint osteoarthritis: a randomised, double blind, placebo controlled trial.

OBJECTIVE: To determine whether a multimodal physiotherapy programme including taping, exercises, and massage is effective for knee osteoarthritis, and if benefits can be maintained with self management. METHODS: Randomised, double blind, placebo controlled trial; 140 community volunteers with knee osteoarthritis participated and 119 completed the trial. Physiotherapy and placebo interventions were applied by 10 physiotherapists in private practices for 12 weeks. Physiotherapy included exercise, massage, taping, and mobilisation, followed by 12 weeks of self management. Placebo was sham ultrasound and light application of a non-therapeutic gel, followed by no treatment. Primary outcomes were pain measured by visual analogue scale and patient global change. Secondary measures included WOMAC, knee pain scale, SF-36, assessment of quality of life index, quadriceps strength, and balance test. RESULTS: Using an intention to treat analysis, physiotherapy and placebo groups showed similar pain reductions at 12 weeks: -2.2 cm (95% CI, -2.6 to -1.7) and -2.0 cm (-2.5 to -1.5), respectively. At 24 weeks, pain remained reduced from baseline in both groups: -2.1 (-2.6 to -1.6) and -1.6 (-2.2 to -1.0), respectively. Global improvement was reported by 70% of physiotherapy participants (51/73) at 12 weeks and by 59% (43/73) at 24 weeks. Similarly, global improvement was reported by 72% of placebo participants (48/67) at 12 weeks and by 49% (33/67) at 24 weeks (all p>0.05). CONCLUSIONS: The physiotherapy programme tested in this trial was no more effective than regular contact with a therapist at reducing pain and disability.

Aged↗

PubMed2005

Risk factors for hamstring injuries in community level Australian football.

OBJECTIVES: To identify risk factors for hamstring injury at the community level of Australian football. METHODS: A total of 126 community level Australian football players participated in this prospective cohort study. To provide baseline measurements, they completed a questionnaire and had a musculoskeletal screen during the 2000 preseason. All were monitored over the season. Injury surveillance and exposure data were collected for the full season. Survival analysis was used to identify independent predictors of hamstring injury. RESULTS: A hamstring injury was the first injury of the season in 20 players (16%). After adjustment for exposure, increasing age and decreased quadriceps flexibility were identified as significant independent predictors of the time to sustaining a hamstring injury. Older age (> or =23 years) was associated with an increased risk of hamstring injury (RR 3.8; 95% confidence interval (CI) 1.1 to 14.0; p = 0.044). Players with increased quadriceps flexibility (as measured by the modified Thomas test) were less likely to sustain a hamstring injury (RR 0.3; 95% CI 0.1 to 0.8; p = 0.022). CONCLUSIONS: The findings of this study can be used in the development of hamstring injury prevention strategies and to identify Australian football players at increased risk of hamstring injury.

Adult↗

PubMed2004

Effect of experimentally induced knee pain on standing balance in healthy older individuals.

OBJECTIVE: Standing balance is impaired in older individuals with knee pain. The extent to which this impairment is due to the effects of pain itself or other pathophysiological aspects related to the underlying musculoskeletal condition causing the pain is unclear. To isolate the influence of pain, this study evaluated the effect of experimentally induced knee pain on standing balance in healthy older individuals. METHODS: We used a repeated-measures, within-subject design involving 12 healthy individuals aged 50-60 yr and with no history of knee pathology. Balance was tested during two randomly allocated experimental conditions: (i) control and (ii) knee pain induced by injection of hypertonic saline into the infrapatellar fat pad. Balance was measured using a computerized force platform under static and dynamic conditions as well as via the functional step test. RESULTS: Standing balance was not significantly altered by experimentally induced acute knee pain, nor was there any relationship between the severity of reported pain and balance scores. CONCLUSIONS: Impairments in balance associated with knee conditions such as osteoarthritis may be due to factors other than the sensation of pain. Thus, strategies designed to reduce pain in treatment of knee pathology may not necessarily lead to improvements in balance. Further research is required to determine the exact causes of balance impairment in individuals with knee joint pain and pathology.

Acute Disease↗

PubMed2003

Does the application of tape influence quadriceps sensorimotor function in knee osteoarthritis?

OBJECTIVES: Using additional data from two previously reported studies, the aim was to determine the effects of immediate and short-term continuous (3 weeks) application of knee tape on quadriceps sensorimotor function in individuals with symptomatic knee osteoarthritis (OA). METHODS: A within-subjects study (n = 18) and a randomized controlled trial (n = 87) were performed using community volunteers. Therapeutic tape (patellar realignment and soft-tissue unloading) was compared with control (placebo) tape and no tape. Outcome measures included knee joint position sense, isometric quadriceps strength and electromyographic quadriceps onset during stair descent. RESULTS: Application of therapeutic tape worsened joint position sense (variable error) at a knee angle of 40 degrees (P < 0.01), but did not immediately alter any other sensorimotor parameter. Even after 3 weeks of wearing tape continuously, sensorimotor function was not altered. Furthermore, no differential effect of tape was noted when participants were dichotomized into those with poor and good sensorimotor scores at baseline. CONCLUSIONS: Neither immediate application nor continuous use of tape (for 3 weeks) appears to influence sensorimotor function in people with knee OA. Alterations in sensorimotor function cannot explain the pain-relieving effects of therapeutic tape observed in this population.

Aged↗

PubMed2003

Immediate effects of adhesive tape on pain and disability in individuals with knee osteoarthritis.

OBJECTIVES: To evaluate the effects of two knee taping techniques, therapeutic tape and neutral tape, on pain and observed disability in symptomatic generalized knee osteoarthritis (OA). METHODS: Using a within-subjects study design, 18 participants were tested under three conditions in random order: untaped, wearing therapeutic knee tape and wearing neutral knee tape. Outcome measures included assessment of pain during each of four activities (using a visual analogue scale) and assessment of observed disability (walking speed, timed up and go test, and the step test). RESULTS: Therapeutic tape significantly reduced pain on three of the four activities assessed, when compared with the neutral and untaped conditions (P<0.017). The only statistically significant change in observed disability was detected in the step test (P<0.001), in favour of the therapeutic tape. CONCLUSIONS: Therapeutic knee tape is a simple, inexpensive strategy that increases the treatment options for therapists and patients in the conservative management of knee OA. Whilst effective in immediately reducing pain, it does not appear to have a significant immediate impact on observed disability associated with the disease. Therapeutic tape may be used as an adjunct to drug and exercise therapies, potentially augmenting the individual benefits of each.

Aged↗

PubMed2003

How valid is a self reported 12 month sports injury history?

BACKGROUND: A past injury history is one of the most commonly cited risk factors for sports injury. Often, injury history data are collected by self report surveys, with the potential for recall bias. OBJECTIVE: To assess the accuracy of a 12 month injury history recall in a population of 70 community level Australian football players. METHODS: The retrospective, self reported injury histories of 70 community level Australian football players were compared with prospective injury surveillance records for the same 12 month period. The accuracy of the players' recall of the number of injuries, injured body regions, and injury diagnosis was assessed. RESULTS: Recall accuracy declined as the level of detail requested increased. All players could recall whether or not they were injured during the previous year. Almost 80% were able to accurately recall the number of injuries and body regions injured, but not the diagnoses, whereas only 61% were able to record the exact number, body region, and diagnosis of each injury sustained. DISCUSSION: The findings of this study highlight the difficulty of using retrospectively collected injury data for research purposes. Any injury research relying on self reported injury history data to establish the relation between injury history and injury risk should consider the validity of the self report injury histories.

Adult↗

PubMed2002

Quantitative ultrasound assessment of acute bone loss following spinal cord injury: a longitudinal pilot study.

Spinal cord injury (SCI) results in substantial and rapid osteoporosis. Given its rapid onset, assessment of bone changes in the early stages (first 6 months) following SCI is important. This is particularly pertinent if intervention is to be implemented. Quantitative ultrasound (QUS) represents a potential assessment tool for the evaluation of skeletal changes in the early stages following SCI. This longitudinal pilot study assessed changes in QUS measures of calcaneal broadband ultrasound attenuation (BUA) and speed of sound (SOS) in 15 male subjects (age 23.9+/-7.3 years) over a 6-week period. Their mean time since SCI was 110.3+/-34.5 days. Also assessed were bone mineral density of the calcaneus (BMDc) and proximal tibia (BMDt) using dual-energy X-ray absorptiometry (DXA). Confirming the rapid onset of bone loss following SCI, BMDc and BMDt decreased by 7.5+/-3.0% ( p<0.001) and 5.3+/-4.2% ( p<0.001), respectively. QUS was sensitive to these changes. BUA decreased by 8.5+/-6.9% ( p<0.001), whilst SOS decreased by 1.5+/- 1.3% ( p<0.001). Suggesting an influence of the material properties of bone on BUA, BUA was correlated with BMDc at both the initial ( r = 0.68, p<0.01) and final ( r = 0.62, p<0.01) assessments. There were no significant correlations in the magnitude of change over the 6-week assessment period between any of the skeletal measures (all p>0.05). This suggests that skeletal qualities other than material properties also influence QUS measures. Overall, this study confirmed the rapid onset of bone loss following SCI and showed QUS to be a useful portable measure of acute bone changes. This may allow assessment of bone loss and the efficacy of intervention on this loss in the early stages following injury, a period where traditional axial DXA assessment is limited by practical constraints.

Absorptiometry, Photon↗

PubMed2002

Balance impairments in individuals with symptomatic knee osteoarthritis: a comparison with matched controls using clinical tests.

OBJECTIVES: To compare balance in individuals with symptomatic knee osteoarthritis (OA) and in age-, gender- and body-mass-matched controls using simple clinical measures. METHODS: Thirty-three people with OA and 33 controls participated. Static postural sway [antero-posterior (AP), lateral and total] was measured using a swaymeter on two different surfaces and under two visual conditions. Dynamic standing balance was assessed using the 'step test'. RESULTS: Both groups displayed similar postural sway on most variables measured. Significantly greater sway was noted in the OA group on a firm surface in both lateral (eyes open) and AP directions (eyes closed), as well as total sway (eyes closed) (P < 0.05). Poorer dynamic standing balance was observed in the OA group as evidenced by the step test (P < 0.0001). CONCLUSIONS: Balance deficits can be identified in the osteoarthritic population using simple, inexpensive measures. However, the clinical relevance of the small deficits identified remains unknown and warrants further investigation.

Aged↗

PubMed2001

Low-intensity pulsed ultrasound stimulates a bone-forming response in UMR-106 cells.

Low-intensity (<100 mW/cm(2)) pulsed ultrasound (US) is an established therapy for fracture repair. In both animal and human trials, such US has been shown to facilitate fresh fracture repair and initiate healing in fractures with repair defects. However, the mechanism by which US achieves these outcomes is not clear. One possible mechanism is the direct stimulation of bone formation. To investigate this hypothesis, the current study investigated the mRNA response of isolated bone-forming cells (UMR-106 cells) to a single 20-min dose of low-intensity pulsed US. Using a novel US-cell coupling method, US was found to stimulate expression of the immediate-early response genes c-fos and COX-2 and elevate mRNA levels for the bone matrix proteins ALP and OC. These findings suggest that low-intensity pulsed US has a direct effect on bone formation. This may contribute to the beneficial effect of low-intensity pulsed US on fracture repair.

Alkaline Phosphatase↗

PubMed2001

A comparison of overground and treadmill running for measuring the three-dimensional kinematics of the lumbo-pelvic-hip complex.

OBJECTIVE: To compare overground and treadmill running for differences in the three-dimensional angular kinematics of the lumbo-pelvic-hip complex. DESIGN: A within-subject repeated measures design. BACKGROUND: The treadmill is an attractive research instrument as speed and slope are easily controlled and the required calibration volume is reduced. However, the degree to which treadmill running simulates overground running has not been resolved in the literature to date. METHODS: 10 able-bodied subjects ran overground and on a treadmill at a self-selected speed. The treadmill speed was matched to each subjects respective average overground speed. The time-distance and the three-dimensional angular kinematic data were captured using a passive marker based motion analysis system. A set of angular and temporal kinematic parameters were extracted from the data and subjected to statistical analyses. RESULTS: Significant differences were found between overground and treadmill running for all the time-distance parameters. Despite this, the kinematics of the lumbar spine and pelvis were similar between the two running conditions, with only three parameters being significantly different. These were lumbar extension at initial contact, anterior pelvic tilt at initial contact and the first maximum anterior pelvic tilt. Hip flexion-extension parameters were also only found to display subtle differences. Of the 17 hip parameters analysed, only hip flexion at initial contact, maximum hip flexion at loading response, hip extension at toe off, maximum hip extension and hip flexion-extension range of motion were found to be significantly different. CONCLUSION: A high powered treadmill with a minimal belt speed fluctuation is capable of being used to obtain a representation of the typical three-dimensional kinematic pattern of the lumbo-pelvic-hip complex during running. RELEVANCE: In order for the treadmill to be accepted as a useful research and/or clinical assessment instrument, it must be demonstrated that it does not significantly alter the performance of the evaluated activity. In this respect, a treadmill with minimal intra-stride belt speed variability and similar surface stiffness to the relevant overground condition is likely to be capable of being used to obtain a representation of the typical human running action for well accommodated subjects.

Adult↗

PubMed2001

Skeletal effects of low-intensity pulsed ultrasound on the ovariectomized rodent.

Growing evidence supports low-intensity pulsed ultrasound (US) as an osteogenic mechanical stimulus. Its effects on isolated bone cells and on fractured bone are established. However, its effects on osteoporosis are not clear. This study examined US effects on ovariectomy (OVX) induced bone changes within the rodent hindlimb (distal femur and proximal tibia), and on normal bone in animals following sham-OVX. Animals were exposed to daily unilateral active-US and contralateral inactive-US for 12 weeks. Bone status was assessed using dual energy X-ray absorptiometry and histomorphometry. Ovariectomy resulted in significant bone changes. Low-intensity pulsed US did not influence these changes. These results suggest that the US dose introduced may not be a beneficial treatment for osteoporosis, and that intact bone may be less sensitive to US than fractured bone and isolated bone cells. This may relate to the biophysical mechanisms of action of US, US-bone interactions and tissue level processes taking place.

Absorptiometry, Photon↗

PubMed2001

The effect of differing Cardan angle sequences on three dimensional lumbo-pelvic angular kinematics during running.

The variability in the three dimensional (3D) lumbo-pelvic angular kinematic patterns during running when using differing Cardan angle sequences was quantified. Data for four able-bodied subjects running on a treadmill at 4.0 m/s were captured using a motion analysis system with six cameras operating at 200 Hz. The adjusted coefficient of multiple correlation was used to compare graphical waveforms whilst the maximum root mean square of the differences was used to express the magnitude of any discrepancy in absolute units. Minimal qualitative differences were found between the various sequences. Quantitative differences between each of the Cardan angle sequences were not found to exceed 7.0 degrees and 2.8 degrees for the lumbar spine and pelvic rotations respectively. It was concluded that different Cardan angle sequences were not found to substantially affect typical 3D lumbo-pelvic angular kinematic patterns during running.

Adult↗

PubMed2001

Efficacy of low-intensity pulsed ultrasound in the prevention of osteoporosis following spinal cord injury.

Ultrasound (US), a high-frequency acoustic energy traveling in the form of a mechanical wave, represents a potential site-specific intervention for osteoporosis. Bone is a dynamic tissue that remodels in response to applied mechanical stimuli. As a form of mechanical stimulation, US is anticipated to produce a similar remodeling response. This theory is supported by growing in vitro and in vivo evidence demonstrating an osteogenic effect of pulsed-wave US at low spatial-averaged temporal-averaged intensities. The aim of this study was to investigate whether low-intensity pulsed US could prevent calcaneal osteoporosis in individuals following spinal cord injury (SCI). Fifteen patients with a 1-6 month history of SCI were recruited. Active US was introduced to one heel for 20 min/day, 5 days/week, over 6 weeks. The contralateral heel was simultaneously treated with inactive US. Patients were blind to which heel was being actively treated. Active US pulsed with a 10 microsec burst of 1.0 MHz sine waves repeating at 3.3 kHz. The spatial-averaged temporal-averaged intensity was set at 30 mW/cm(2). Bone status was assessed at baseline and following the intervention period by dual-energy X-ray absorptiometry and quantitative US. SCI resulted in significant bone loss. Bone mineral content decreased by 7.5 +/- 3.0% in inactive US-treated calcanei (p < 0.001). Broadband US attenuation and speed of sound decreased by 8.5 +/- 6.9% (p < 0.001) and 1.5 +/- 1.3% (p < 0.001), respectively. There were no differences between active and inactive US-treated calcanei for any skeletal measure (p > 0.05). These findings confirm the negative skeletal impact of SCI, and demonstrate that US at the dose and mode administered was not a beneficial intervention for SCI-induced osteoporosis. This latter finding may primarily relate to the inability of US to effectively penetrate the outer cortex of bone due to its acoustic properties.

Absorptiometry, Photon↗