A mixed-method approach to examining the experiences of allied health clinicians and managers of the performance, appraisal and development framework in a regional health care service

INTRODUCTION

Evaluating employee performance is important for organisational success however, limited research exists across the allied health workforce.

OBJECTIVE

This study investigated allied health clinician and manager experiences and perceptions of the appropriateness of the performance and development (PAD) framework.

DESIGN

A mixed methods design with purposive sampling was conducted in a medium size hospital and health service in regional Queensland to investigate the appropriateness of the PAD framework. A 29 item online survey collected likert scale and open ended responses. Identified respondents also completed a semi-structured interview. Aggregated satisfaction scores identifying PAD alignment, processes, education, resources and perceptions were analysed to identify organisational PAD appropriateness. Themes from interviews provided concurrent experiential data.

FINDINGS

Eighty-five respondents completed the online survey and 20 interviews were conducted. A Chi-Square Goodness of Fit test revealed a significant (p < 0.05) clinician (n = 75) response of moderate dissatisfaction (36%) for the PAD framework, while managers (n = 10) were neither dissatisfied nor satisfied (50%) or moderately satisfied (40%). Clinician aggregated agreement responses were significantly (p < 0.05) higher for PAD alignment (45%), processes (63%), education (49%) and lower for feedback (33%) and resources (28%). Manager aggregated agreement responses were high for PAD alignment (85%), processes (55%), education (57%), feedback (65%) and perceptions (50%). Interviews (n = 20) revealed three themes: uncertainty around PAD framework; expectations for experienced leadership and importance of discipline specific knowledge.

DISCUSSION

This study draws on both clinician and manager input to assess the overall PAD framework with responses favouring clinician dissatisfaction to the current process.

CONCLUSION

The PAD framework is valuable for staff development when there is positive rapport and discipline alignment between both clinician and manager. Successful staff appraisals require efficient and appropriate documentation that promotes individual development, clinical performance and organisational priorities.

A Structured E-Investigation Into the Prevalence and Acceptance of Smartphone Applications by Exercise Professionals

Bromilow, L, Stanton, R, and Humphries, B. A structured e-investigation into the prevalence and acceptance of smartphone applications by exercise professionals. J Strength Cond Res 34(5): 1330-1339, 2020-The primary purpose of this study was to examine the prevalence and acceptance of smartphone applications by exercise professionals when interacting with clients and patients. A 29-item anonymous online survey was designed, containing separate sections on demographics, smartphone proficiency, benefits and barriers to using smartphones, and use of smartphones in a professional setting. Accredited members of the Australian Strength and Conditioning Association, and Exercise and Sports Science Australia received an information sheet through organizational communication channels, inviting them to participate. Two hundred forty-nine exercise professionals completed the survey, with men (71%; n = 176) accounting for most of the respondents. Proficiency using smartphone applications is predominantly-advanced (37%; n = 92), intermediate (33%; n = 82), or expert (14%; n = 35). Identified strategies to find smartphone applications included personal searches (67%; n = 167) and colleague recommendations (55%; n = 137). Reported benefits include fast access to information (67%; n = 167), saves time for record keeping (56%; n = 141), and allows performance tracking (55%; n = 138). Almost all respondents (92%; n = 229) identified barriers, such as inexperience with using particular applications (42%; n = 105). Almost all respondents (96%; n = 239) reported they would recommend smartphone applications to clients and patients, primarily for self-tracking (53%; n = 132). Smartphone use among exercise professionals is prevalent; however, application and sensor technology are reluctantly underused. Increasing acceptance requires embedding within educational curricula, recognition from professional organizations, and collaboration with, to maximize the potential capabilities of smartphone technology within working environments.

Abstract P1-01-11: Not presented

This abstract was not presented at the symposium.

Abstract P6-01-09: MiRNA-200b suppresses triple negative breast cancer metastasis by targeting ARHGAP18 and causing sustained Rho A activation

This abstract was not presented at the symposium.

Predicting groundwater redox status on a regional scale using linear discriminant analysis

Reducing conditions are necessary for denitrification, thus the groundwater redox status can be used to identify subsurface zones where potentially significant nitrate reduction can occur. Groundwater chemistry in two contrasting regions of New Zealand was classified with respect to redox status and related to mappable factors, such as geology, topography and soil characteristics using discriminant analysis. Redox assignment was carried out for water sampled from 568 and 2223 wells in the Waikato and Canterbury regions, respectively. For the Waikato region 64% of wells sampled indicated oxic conditions in the water; 18% indicated reduced conditions and 18% had attributes indicating both reducing and oxic conditions termed "mixed". In Canterbury 84% of wells indicated oxic conditions; 10% were mixed; and only 5% indicated reduced conditions. The analysis was performed over three different well depths, <25m, 25 to 100 and >100m. For both regions, the percentage of oxidised groundwater decreased with increasing well depth. Linear discriminant analysis was used to develop models to differentiate between the three redox states. Models were derived for each depth and region using 67% of the data, and then subsequently validated on the remaining 33%. The average agreement between predicted and measured redox status was 63% and 70% for the Waikato and Canterbury regions, respectively. The models were incorporated into GIS and the prediction of redox status was extended over the whole region, excluding mountainous land. This knowledge improves spatial prediction of reduced groundwater zones, and therefore, when combined with groundwater flow paths, improves estimates of denitrification.

Validity of a Smartphone-Based Application for Determining Sprinting Performance

Recent innovations in smartphone technology have led to the development of a number of applications for the valid and reliable measurement of physical performance. Smartphone applications offer a number of advantages over laboratory based testing including cost, portability, and absence of postprocessing. However, smartphone applications for the measurement of running speed have not yet been validated. In the present study, the iOS smartphone application, SpeedClock, was compared to conventional timing lights during flying 10 m sprints in recreationally active women. Independent samples t-test showed no statistically significant difference between SpeedClock and timing lights (t(190) = 1.83, p = 0.07), while intraclass correlations showed excellent agreement between SpeedClock and timing lights (ICC (2,1) = 0.93, p = 0.00, 95% CI 0.64-0.97). Bland-Altman plots showed a small systematic bias (mean difference = 0.13 seconds) with SpeedClock giving slightly lower values compared to the timing lights. Our findings suggest SpeedClock for iOS devices is a low-cost, valid tool for the assessment of mean flying 10 m sprint velocity in recreationally active females. Systematic bias should be considered when interpreting the results from SpeedClock.

Moderate-intensity running causes intervertebral disc compression in young adults

BACKGROUND

Decreased intervertebral disc (IVD) volume can result in diminished load-carrying capacity of the spinal region. Although moderate-intensity running is generally advocated for apparently healthy adults, running causes a loss in stature that is thought to reflect IVD compression. The aim of this investigation was to use magnetic resonance imaging (MRI) to quantify the influence of moderate-intensity treadmill running on IVD height and volume in the thoracic and lumbar regions of the vertebral column.

METHODS

A clinic-based repeated-measures design was used in eight healthy young asymptomatic adults. After preliminary measurements and familiarization (day 1), participants reported to the clinic on two further occasions. MRI scans and stature measurements were completed at baseline (day 2), preexercise (day 3), and after 30 min of moderate-intensity treadmill running (postexercise, day 3). Mean height and volume were derived for all thoracic and lumbar IVDs from digitized MRIs, and stature was determined with a stadiometer.

RESULTS

Moderate-intensity running resulted in 6.3% ± 0.9% reduction in mean IVD height and 6.9% ± 1.0% reduction in calculated IVD volume. The day-to-day variation in mean IVD height and volume were 0.6% ± 0.6% and 0.4% ± 0.6%, respectively.

CONCLUSIONS

This is the first study to quantify the influence of moderate-intensity running on IVD height and volume. Changes in IVD height and volume were observed throughout the thoracic and lumbar vertebral regions. These findings suggest that future studies evaluating the influence of various loading activities and recovery techniques on IVD structure should consider thoracic as well as lumbar regions of the spine.

The influence of variable range of motion training on neuromuscular performance and control of external loads

Resistance training programs that emphasize high force production in different regions of the range of motion (ROM) may provide performance benefits. This study examined whether variable ROM (VROM) training, which consists of partial ROM training with countermovements performed in a different phase of the ROM for each set, results in improved functional performance. Twenty-two athletes (age 22.7 ± 2.4 years, height 1.81 ± 0.07 m, and body mass 94.6 ± 14.5 kg) with extensive resistance training backgrounds performed either a VROM or full ROM control (CON) 5-week, concentric work-matched training program. The participants were assigned to a group based on stratified randomization incorporating their strength levels and performance gains in preceding training microcycles. Testing consisted of assessing the force-ROM relationship during isokinetic and isometric bench press and ballistic bench throws, with normalized electromyography amplitude assessed during the isometric tests. Repeated-measure analyses of variance revealed that the VROM intervention significantly (p < 0.05) increased both full ROM bench throw displacement (+15.5%) and half ROM bench throw peak force (+15.7%), in addition to isokinetic peak force in the terminal ROM (13.5% increase). No significant differences were observed in the CON group or between groups for any other outcome measures. Analysis of the force-ROM relationship revealed that that the VROM intervention enhanced performance at shorter muscle lengths. These findings suggest that VROM training improves terminal and midrange performance gains, resulting in the athlete possessing an improved ability to control external loading and produce dynamic force.

An examination of strength and concentric work ratios during variable range of motion training

Variable range of motion (ROM) training consists of partial ROM resistance training with the countermovement being performed at a different phase of the movement for each set. In this study, we assessed the effect of this method of training on peak force, load lifted, and concentric work performed. Six male subjects with resistance training backgrounds (age 20.2 +/- 1.3 years, height 179.4 +/- 4.6 cm, weight 89.6 +/- 9.9 kg, 6-repetition maximum [6RM] bench press 92.5 +/- 14.3 kg) participated in this study. Testing consisted of 6RM bench press strength tests during full (FULL), three quarter ((3/4)), one half ((1/2)), and one quarter ((1/4)) ROM from full elbow extension bench press performed on a Smith machine. The 6RM load, peak force (PF), and concentric work (W) performed during each ROM was examined using a one-way analysis of variance performed at an alpha level of p < 0.05. The 6RM load increased significantly as the ROM was decreased for all tests (FULL = 92.5 +/- 14.3 kg, (3/4) = 102.1 +/- 14.3 kg, (1/2) = 123.3 +/- 23.6 kg, (1/4) = 160.9 +/- 26.2 kg). PF during each test was significantly higher during the (1/4) (1924.8 +/- 557.9 N) and (1/2) (1859.4 +/- 317.1 N) ROM from full elbow extension bench press when compared with the (3/4) (1242.2 +/- 254.6 N) and FULL (1200.5 +/- 252.5 N) ROM exercise. Although higher force levels were evident, the restriction in barbell displacement resulted in a subsequent reduction in W as the lifting ROM was reduced. These results suggest that variable ROM resistance training results in increased force production as the ROM diminishes.

Determining the optimal load for jump squats: a review of methods and calculations

There has been an increasing volume of research focused on the load that elicits maximum power output during jump squats. Because of a lack of standardization for data collection and analysis protocols, results of much of this research are contradictory. The purpose of this paper is to examine why differing methods of data collection and analysis can lead to conflicting results for maximum power and associated optimal load. Six topics relevant to measurement and reporting of maximum power and optimal load are addressed: (a) data collection equipment, (b) inclusion or exclusion of body weight force in calculations of power, (c) free weight versus Smith machine jump squats, (d) reporting of average versus peak power, (e) reporting of load intensity, and (f) instructions given to athletes/ participants. Based on this information, a standardized protocol for data collection and reporting of jump squat power and optimal load is presented.

Female collegiate windmill pitchers: influences to injury incidence

Few studies have examined fast-pitch softball pitchers and associated injuries. The aim of this study was to investigate injuries occurring to collegiate softball pitchers and associated influential factors. A web-based survey of 181 Division I (n = 45), II (n = 30), and III (n = 54) collegiate softball pitchers was conducted. The survey involved self-reported data from the previous year that addressed (a) demographic information, (b) pitching and game data, (c) training program information, and (d) injury reporting. Demographic information, pitching and game data, and training program information were not statistically significant (p < 0.05) in relation to injury. Descriptive statistics were used to report totals and percentages of pitchers surveyed. Among 131 reported injuries, 36 were acute, 92 chronic/overuse, and 3 unspecified. Of the total injuries, 80 were directly from pitching, with 33 shoulder-related and 16 related to the lower back. Among injured pitchers, 109 took nonsteroidal anti-inflammatory drugs, 140 used modalities, 11 received surgeries, and 95 saw additional specialists. Pitchers are at a risk for injury, with 72.8% of surveyed pitchers being injured during the 2001-02 year.

The effect of short-term Swiss ball training on core stability and running economy

The purpose of this study was to investigate the effect of a short-term Swiss ball training on core stability and running economy. Eighteen young male athletes (15.5 +/- 1.4 years; 62.5 +/- 4.7 kg; sigma9 skinfolds 78.9 +/- 28.2 mm; VO2max 55.3 +/- 5.7 ml.kg(-1).min(-1)) were divided into a control (n = 10) and experimental (n = 8) groups. Athletes were assessed before and after the training program for stature, body mass, core stability, electromyographic activity of the abdominal and back muscles, treadmill VO2max, running economy, and running posture. The experimental group performed 2 Swiss ball training sessions per week for 6 weeks. Data analysis revealed a significant effect of Swiss ball training on core stability in the experimental group (p < 0.05). No significant differences were observed for myoelectric activity of the abdominal and back muscles, treadmill VO2max, running economy, or running posture in either group. It appears Swiss ball training may positively affect core stability without concomitant improvements in physical performance in young athletes. Specificity of exercise selection should be considered.

Design of a Controlled-Release Ergometer for the Measurement of Musculotendinous Stiffness of the Knee Flexors

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

Neuromechanical strategies employed to increase jump height during the initiation of the squat jump

The maximal height attained in a vertical jump is heavily influenced by the execution of a large countermovement prior to the upward motion. When a jump must be executed without a countermovement, as in a squat jump, the maximal jump height is reduced. During such conditions, the human body may use other strategies in order to increase performance. The purpose of this research was to investigate the effects of two strategies employed during the initiation of the squat jump: the premovement silent period (PSP), and the small amplitude countermovement (SACM). Fifteen elite male volleyball players (20.6 +/- 1.6 years) and 13 untrained males (20.2 +/- 1.7 years) performed 10 maximal effort squat jumps from identical starting positions. The electromyographic activity of the vastus lateralis and biceps femoris was measured in conjunction with the vertical ground reaction force and vertical displacement. It was found that the presence of a PSP or a SACM of 1-3 cm did not increase maximal squat jump height significantly (p > 0.05), in neither the highly trained athletes nor the untrained individuals. These results suggest that these strategies do not play a major role in the determination of jump height. Researchers have assumed that a squat jump is purely concentric, and that there are no facilitating mechanisms present that may influence the performance of the jump. This study provides evidence to support this assumption.

The Influence of Vibration on Muscle Activation and Rate of Force Development during Maximal Isometric Contractions

At present there appears to be a need for research conducted on the effects of vibration on the contractile ability of skeletal muscle tissue. The aim of this study was to address this issue by examining the effects of a superimposed muscle/tendon vibration at 50.42±1.16 Hz (acceleration 13.24 ± 0.18ms(-2): displacement ≈5mm) on muscular activation and maximal isometric contraction. Sixteen participants with a mean age, body mass, and height of 22 ± 4.4 years, 73.2 ± 11.7 kg and 173.1 ± 9.7 cms, respectively, were recruited for this study. Electromyography and accelerometry from the rectus femoris, and maximal isometric force data characteristics were collected from the dominant limb under conditions of vibration, and no-vibration. A superimposed 50 Hz vibration was used during the contraction phase for the maximal isometric leg extension for the condition of vibration. A one-way ANOVA revealed no significant (p > 0.05) differences between the vibration and no-vibration conditions for peak normalized EMGRMS (84.74% Vs 88.1%) values. An ANOVA revealed significant (p > 0.05) differences between the peak fundamental frequencies of the FFT between the conditions vibration (27.1 ± 12.2 Hz) and no-vibration (9.8 ± 3.5 Hz). Peak isometric force, peak rate of force development, rate of force development at times 0.05, 0.01, 0.1, 0.5 seconds, and rate of force development at 50, 75, and 90% of peak force were not significantly different. The results of this study suggest that the application of vibration stimulation at 50 Hz during the contraction does not contribute to muscle activation, or enhance force production for maximal isometric contractions. Key PointsThe application of a vibratory stimulation to the human body increases the normal acceleration resulting in an increase in force and a change in performanceThis study was to address this issue by examining the effects of a direct superimposed muscle/tendon vibration at 50 Hz on isometric strength characteristicsNo improvement or change in isometric force or rate of force developmentNo changes to peak normalized EMGRMS values.

Discriminating between elderly and young using a fractal dimension analysis of centre of pressure

The aim of this project was to evaluate the use of a new analysis technique, fractal dimension analysis, for quantification of quiet stance centre of pressure (COP). By using a fractal dimension analysis of COP, it might be possible to gain more information about control during quiet stance than traditional analyses have previously allowed. The current project considered a group of young healthy participants and a group of elderly healthy participants to compare traditional measures of COP against a fractal dimension analysis of COP. Results indicated that both types of analyses are able to distinguish between eyes open and eyes closed in the elderly group. However, the fractal dimension analysis more accurately detected differences between the participant groups when standing with their eyes closed. Based on these results it is suggested that fractal dimension analysis is more informative about posture control than traditional measures. It is suggested that a fractal dimension type of analysis can be incorporated into clinical testing to identify patients with pathologies.

Self-reported training habits of Australian outrigger canoe paddlers

The purpose of this descriptive study was to investigate training habits of Australian outrigger canoe paddlers. A 1-page questionnaire was hand-delivered to 101 paddlers. The survey addressed training factors, use of supplementary training, ergogenic aids, sports performance professionals, and injury history. Paddlers train for an average of 3.2 on-water sessions per week, with each session lasting an average of 1.7 hours. The 6-person canoe is favored by 55% of paddlers surveyed. Seventy-one percent of paddlers use strength training to accompany paddling with a mean frequency of 2.5 sessions per week. Seventy-four percent of paddlers report additional cross-training, with a mean of 3.1 sessions per week. Ergogenic aids are used by 55% of paddlers, and 52% utilize the services of sports science or sports medicine personnel. Forty-nine percent of paddlers (n = 49) report injuries related to paddling, with the most common sites being the shoulder and lower back.

The effects of timing and application of vibration on muscular contractions

BACKGROUND

The effect of vibration stimulation on muscular strength is an emerging field of research and very little comprehensive work has been conducted at this stage.

HYPOTHESIS

There will be no effects of timing or application of vibration stimulation on muscular strength and activation across isometric, isokinetic and concentric isotonic contractions.

METHODS

There were 28 recreational athletes who participated in this study. Their characteristics were: (mean +/- SD) age, 22.8 +/- 5.6 yr; height, 174.1 +/- 8.8 cm; and body mass, 78.0 +/- 13.6 kg. The vibration stimulation was delivered at 50.42 +/- 1.16 Hz with an acceleration of 13.24 +/- 0.18 ms(-2).

RESULTS

A series of one-way ANOVAs revealed significant (p < 0.05) improvements of 14.7 +/- 2.9% and 15.3 +/- 3.1% above normal contraction levels for concentric isotonic strength during and after the vibration stimulation, respectively. No significant improvements in isometric and isokinetic strength were evident. Concurrent measurement of electromyography (EMG) presented significant improvements during stimulation of 30.1 +/- 14.6%, 43.0 +/- 13.0%, and 107.1 +/- 44.4% in mean activation of rectus femoris (RF) for the isometric, isokinetic, and concentric isotonic contractions, respectively. Synchronous collection of vibromyography (VMG) during stimulation displayed a significant decrease of -6.4 +/- 1.5%, -5.1 +/- 1.2%, and -4.1 +/- 1.7% in mean VMG activity of RF for the isometric, isokinetic, and concentric isotonic contractions, respectively.

CONCLUSIONS

Significant improvements in muscular strength and activation for concentric isotonic contractions performed during an applied vibration suggest that the optimal timing of a vibratory stimulation would be while the participant is contracting isotonically. However, further research needs to be conducted to establish the exact mechanism behind these improvements.

Identifying bone mass and muscular changes

The aim of this investigation was to examine the impact of a six-month high intensity strength-training program on lumbar bone mineral density (BMD), trunk and lower limb strength in a population of Australian women aged 50 years and over. A subject pool of 44 women were recruited and randomly allocated into either strength training (n = 19) or active control (n = 25) groups. All subjects trained twice weekly in either a 50 minute supervised strength training session that progressed from 60% one repetition maximum (1RM) to 90% 1RM or a 50 minute group walk session. Measurements included a lumbar (L2-L4) BMD scan: peak isokinetic trunk strength and a dynamic 1RM squat as a measure of lower body strength. No significant group differences in lumbar BMD were evident at the completion of training. However, a significant (p < 0.05) within group change was apparent for the active control group as lumbar BMD decreased 1.7% below baseline testing. A significant (p < 0.05) group difference was evident with the strength trained group increasing peak isokinetic trunk strength (19.3%) and 1RM squat strength (34.4%) above that of the active controls. It was concluded that strength training provides an effective means for increasing trunk and lower limb strength in women over 50 years. The impact of strength training on lumbar BMD was not conclusive in the present study.

Kinanthropometric and physiological characteristics of outrigger canoe paddlers

We describe the physiological characteristics of amateur outrigger canoe paddlers. Twenty-one paddlers (13 males, 8 females) were evaluated for body stature, aerobic power, muscular strength and endurance, peak paddle force, flexibility and 250 m sprint paddle performance at the end of the outrigging season. The mean variables (+/- s) for the males were: age 27 +/- 9 years, height 175 +/- 5 cm, body mass 80 +/- 5 kg, arm span 178 +/- 7 cm, sitting height 100 +/- 2 cm, aerobic power 3.0 +/- 0.4 l x min(-1), maximum bench press strength 85 +/- 19 kg, right peak paddle force 382 +/- 66 N and left peak paddle force 369 +/- 69 N. For the females, these were: age 26 +/- 6 years, height 168 +/- 5 cm, body mass 70 +/- 8 kg, arm span 170 +/- 5 cm, sitting height 97 +/- 3 cm, aerobic power 2.3 +/- 0.51 l x min(-1), maximum bench press strength 47 +/- 10 kg, right peak paddle force 252 +/- 63 N and left peak paddle force 257 +/- 60 N. Analysis of variance revealed differences (P < 0.05) between the dominant and non-dominant sides of the body for peak paddle force, isokinetic internal and external rotation, and flexion and extension torque of the shoulder joint. The outrigger canoe paddlers were generally within the range of scores found to describe participants of other water craft sports. Outrigger canoeists should be concerned with the muscular strength imbalances associated with paddling technique.

Effect of exercise intensity on bone density, strength, and calcium turnover in older women

PURPOSE

This study examined the effects of 24 wk of high intensity strength training or low intensity walking on lumbar bone mineral density (BMD), muscular strength, and calcium turnover in Australian women either taking hormone replacement therapy (HRT) or not taking HRT.

METHODS

A subject pool of 64 women between 45-65 yr and randomly allocated into weights (N = 21), walking (N = 20), weightsHRT (N = 14), and walkingHRT (N = 9) groups completed this study. All subjects trained twice weekly in either a 50-min walking or weight-training program (60-90% IRM). Measurements included maximal isometric knee strength, IRM bench press, IRM squat, isokinetic back strength, lumbar (L2-L4) BMD, serum osteocalcin, and urinary deoxypyridinoline crosslinks (Dpd).

RESULTS

No significant group differences in BMD were evident at the completion of training. However, a significant (P < 0.05) within group change was apparent for the walking group since BMD decreased 1.3% below baseline testing. Osteocalcin levels increased significantly (P < 0.05) in the walking (22%) group. Maximal bench press and squat strength improved significantly (P < 0.05) in the weights (25.8% and 37.7%) and weightsHRT (25.4% and 35.7%) groups. The weights group also increased significantly (P < 0.05) in isokinetic back strength (22.2%).

CONCLUSION

It was concluded that short-term high intensity resistance training provides an effective means for increasing muscular strength in women between 45 and 65 yr. The training effects on lumbar BMD were not apparent in the present study.

1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT) and reduced bone mineral density

The organochlorine pesticide 1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT), is a well-known and widely dispersed "environmental estrogen" (World Health Organization Criteria no. 9; Geneva, Switzerland [1979]). Kelce et al. (Nature, 1995; 375:581-85) recently identified the DDT metabolite, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), has also recently been identified as a potent androgen receptor antagonist. The authors examined the relationship between serum levels of DDE and bone mineral density in 68 sedentary women who reported adequate dietary intake of calcium. Reduced bone mineral density was correlated significantly with age (r = -.36, p = .004), as well as with increases in the log of DDE levels in serum (r = -.27, p = .03). The authors also used multiple-regression analysis to examine the influence of other predictor variables on the relationship between log DDE and bone mineral density. The strongest model (p = .002) included log DDE (p = .018), age (p = .002), and years on hormone replacement therapy (p = .10) as predictor variables, and this model afforded prediction of 21% of bone mineral density variation. These results suggest that past community exposures to DDT may be associated with reduced bone mineral density in women.

The relationship between dynamic, isokinetic and isometric strength and bone mineral density in a population of 45 to 65 year old women

This study investigated the relationship between age, lumbar spine bone mineral density (LS BMD) and muscular strength of peri and postmenopausal women between 45 and 65 years either taking or not taking hormone replacement therapy (HRT). Ninety six women were tested for LS BMD (L2-L4), one repetition maximum (1RM) bench press and squat, maximal voluntary isometric contraction (MVC) of the knee extensors and peak torque of back extensor muscles at a speed of 30 degrees s(-1). Bone and strength data were analysed to evaluate the relationships in incrementing five year age groups and based on groups either taking or not taking HRT. ANOVA revealed significant differences in LS BMD between the 45-49 and 55-59 (F[3,92]=2.6411, p<0.05; -8%) age groups amounting to an annual bone loss of 0.8% for this Australian based population. Non significant LS BMD results were evident after controlling for the influence of age and menopausal status on the groups either taking or not taking HRT. Significant differences between the 45-49 and 60-64 (F[3,92]=2.7463, p<0.05) age groups for 1RM bench press and the 45-49 and 60-64, 50-54 and 60-64, and, 55-59 and 60-64 (F[3,92]=4.2816, p<0.05) age groups for 1RM squat amounting to an 18.8% and 37.5% loss of dynamic upper and lower body strength, respectively. Group correlation coefficients ranged between (r=-0.20 and -0.34, p<0.05) for LS BMD, strength and age. The conclusions demonstrate a concomitant decline in maximal muscle strength and bone density between women 45 and 65 years irrespective of HRT. These results also demonstrate a 50% greater decline in lower body strength compared to upper body strength between women 45 and 65 years.

Electrophoretic separation of myosin heavy chain isoforms in the human m. vastus lateralis: references to reproducibility and relationships with force, electromechanical delay, fibre conduction velocity, endurance and electromyography

The aim of this investigation was to determine the relationship between muscle performance and the myosin heavy chain (MHC) composition and the reliability of electrophoretically determined MHC compositions. A total of thirty-one male subjects participated in the experiments. Maximal voluntary isometric contractions (MVC) of the knee extensors were performed at an arbitrary knee angle of 90 degrees and the following variables were recorded: maximal isometric force, muscle fibre conduction velocity (MFCV), electromechanical delay (EMD), maximal rate of force development (MRFD), median frequency of EMG (MF) and iEMG. Static isometric contractions of the knee extensors were held at an angle of 90 degrees using contractile forces of 10%, 50% and 100% MVC, respectively. These tests were conducted on separate days. Muscle biopsy samples were obtained from the left m. vastus lateralis before MVC and static endurance tests. MHC protein isoform differences were determined through sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE) followed by densitometric analysis. Type I-MHC compositions of the m. vastus lateralis ranged from 20-68% with a mean of 49 +/- 18%, mean type IIa-MHC and type IIb-MHC percentages were 35 +/- 16% and 16 +/- 10%, respectively. MHC compositions of duplicate biopsy samples were not significantly different from that of original samples. The coefficients of variation calculated for duplicate biopsy samples suggested reasonable reproducibility for MHC isoform differentiation for type I-MHC and type-II MHC composition (CV = 12.6%). Differentiation between type IIa-MHC and type IIb-MHC was not always clear using the densitometric traces. Subjects with higher percentages of type II-MHC displayed significantly faster MFCV (r = 0.67, P < 0.1), isometric force development (r = 0.68, P < 0.1) and shorter periods of EMD (r = -0.72, P < 0.05). There was also a tendency toward faster MRFD in these subjects although results did not reach significance. Endurance times for isometric contractions held at 10%, 50% and 100% MVC to exhaustion were not correlated with MHC composition. No relationships between II-MHC composition and MF or iEMG were observed. It was suggested that surface electromyographic recordings obtained during isometric MVC did not reflect underlying differences in muscle fibre composition.

Myoelectric evidence of peripheral muscle fatigue during exercise in severe hypoxia: some references to m. vastus lateralis myosin heavy chain composition

Integrated electromyography (iEMG) of the m. vastus lateralis was analysed during cycle ergometry in male subjects (n = 8). Two work trials were conducted, one under normoxia (N), the other under environmental normobaric hypoxia (EH in which the oxygen fraction in inspired gas = 0.116), each trial lasting 10 min. The absolute power output (180 W) was the same for both trials and was equivalent to 77 (4)% of maximum heart rate in trial N. Maximal voluntary isometric contractions were performed after each trial to assess changes in force, muscle fibre conduction velocity (MFCV), electromechanical delay (EMD), median frequency of EMG (MF) and maximal iEMG (iEMGmax). Biopsy samples of muscle were obtained from the m. vastus medialis before testing. Myosin heavy chain (MHC) differences were determined through sodium dodecyl-polyacrylamide gel electrophoresis followed by densitometric analysis. No differences in submaximal iEMG were observed between EH and N trials during the first minute of work. At the end of both work trials iEMG was significantly elevated compared with starting values, however the iEMG recorded in EH exceeded N values by 15%. At the end of the EH trials the following were observed: a decrease in isometric force, MFCV and MF with an increase in EMD and the iEMGmax/force ratio. The iEMGmax was unchanged. No differences in any of these variables were observed after the N trial. Mean (SD) lactate concentrations following EH and N trials were 9.2 (4.4) mmol x 1(-1) and 3.5 (1.1) mmol x 1(-1), respectively. Results indicate that an increased motor unit recruitment and rate coding was needed in EH to maintain the required power output. The increased motor unit recruitment and rate coding were associated with myoelectric evidence of "peripheral" muscle fatigue. Subjects with higher compositions of type II MHC accumulated more lactate and displayed greater reductions in MF and MFCV during fatigue.

Major surgical intervention during extracorporeal membrane oxygenation

Of 135 patients treated with extracorporeal membrane oxygenation (ECMO) between January 1987 and December 1989, 19 (14.0%) patients underwent surgical procedures while on ECMO. Thirteen (68%) patients had operations related to hemorrhage, including cannula site (6), mediastinal (1), hemoperitoneum (3), and hemothorax (3). Six of 13 patients required repetitive operations for bleeding; 4 of 6 died. Six (35%) patients had operations for congenital pathology including patent ductus (PDA) ligation (2), repair of transposition of the great vessels (2), repair of coarctation (1), and repair of congenital diaphragmatic hernia (3). One patient had multiple simultaneous procedures performed. Of these 6 patients, 4 were decannulated immediately and 2 were decannulated within 28 hours following surgery without any bleeding complications. Fifteen of 19 patients were operated on in the neonatal intensive care unit. The 4 remaining patients required transport on ECMO to the surgical suite. Thirteen of the 19 patients requiring surgical intervention on ECMO survived. In the 13 survivors, the mean time to decannulation postoperative was 45 hours, and in those that died it was 90 hours. Our experience suggests that surgical intervention while on ECMO is technically feasible with the best results achieved when rapid discontinuation of ECMO can be accomplished postoperatively. Due to this fact major surgical intervention should be postponed if possible until near the conclusion of the ECMO therapy.

Persistent pulmonary hypertension complicating cystic adenomatoid malformation in neonates

Neonates with congenital diaphragmatic hernia (CDH) are known to be susceptible to stress-induced persistent pulmonary hypertension (PPHN). Congenital cystic adenomatoid malformations (CCAMs) may also present as respiratory distress in the newborn. Intubation and mechanical ventilation cause clinical deterioration because of air trapping within cystic spaces; these patients require prompt lobectomy. PPHN has not been commonly associated with CCAM. Three patients with CCAM were encountered who developed PPHN postlobectomy. Three newborns, 36 to 38 weeks' gestation, presented with respiratory distress. Two had diagnosis of thoracic tumors on fetal ultrasound (22 and 33 weeks). Chest x-ray at birth confirmed cystic intrathoracic tumors in all and they underwent immediate thoracotomy and lobectomy (1 right upper, 1 left lower, 1 left upper). The patients were stable for 4 hours to 5 days postoperatively and then developed findings consistent with PPHN by cardiac echocardiography and required extracorporeal membrane oxygen (ECMO) support. ECMO was required for 66.5 to 120 hours. Each patient was successfully weaned to conventional ventilatory support. The clinical course of these patients was similar to those with CDH who undergo immediate surgery. The stress of surgical intervention combined with hypoxia and hypercarbia stimulates a hyperactive pulmonary vasculature and the development of PPHN. ECMO provides an effective adjunct to support patients with PPHN on the basis of congenital cystic adenomatoid malformations.

Extracorporeal membrane oxygenation in lambs through umbilical vessel perfusion: cardiac and hepatic complications

Twin lambs were delivered by ceasarean section near term, aralyzed, sedated and randomly assigned to either mechanical ventilation or umbilical arteriovenous ECMO for 48 hours. Umbilical arteriovenous ECMO provided adequate gas exchange with minimal or no ventilation of the native lungs. However, at autopsy, animals treated with umbilical ECMO showed right heart dilation and liver necrosis or hemorrhage compared to their twins treated with mechanical ventilation.

The impact of extracorporeal membrane support in the treatment of congenital diaphragmatic hernia

Neonates with congenital diaphragmatic hernia (CDH) treated by immediate surgical intervention and conventional ventilatory support have an overall poor survival. The potential of extracorporeal membrane oxygenation (ECMO) therapy to improve survival of infants with CDH remains controversial. Comparison was made in a single institution's pre-ECMO and post-ECMO survival statistics to establish efficacy of extracorporeal support for persistent pulmonary hypertension (PPH). This study was accomplished by stratifying patients by an oxygen index (OI). Sixty-eight patients were treated for CDH from 1977 to 1986 without ECMO. Fifty-eight patients underwent repair of CDH within the first 24 hours of life. Data could be retrieved for calculation of the OI in 46 patients. Nineteen patients developed an OI of 40 or greater; one survived (5%). Three of 27 patients with an OI less than 40 died (OIs = 34, 38, and 38). Thirty-one patients were treated from 1987 to 1989 and none were excluded from ECMO based on a minimum PO2. Fifteen had an OI less than 40 (range, 1 to 38), were treated conventionally, and 13 survived (87%). Sixteen patients had an OI greater than 40 and 13 qualified for ECMO. Nine of 13 survived (69%). Comparing pre-ECMO and post-ECMO survival for infants with an OI of 40 or greater (5% v 69%), there is a significant improvement in survival when ECMO is used (P less than .001). ECMO support offers a strong adjunct in management of neonates with CDH who develop PPH.