Elizabeth Gass

Sustainable undergraduate education and professional competency

The primary purpose of Schools of Physiotherapy, and their tradition, is to develop in their students the cognitive and practical breadth required to function as competent practitioners immediately on graduation, with the capacity to continue to learn and develop. As schools within universities, they also seek to provide students with broad educational experiences, assisting them to develop generic skills such as independent learning, teamwork, responsibility towards other people, problem solving abilities and the like.

V˙O2peak and the gas-exchange anaerobic threshold during incremental arm cranking in able-bodied and paraplegic men

Abstract Resting energy expenditure, peak oxygen uptake (V˙O2peak) and the gas-exchange anaerobic threshold (Than) were measured during incremental arm cranking (15 W · min−1) in six able-bodied (AB) and six paraplegic (P) subjects. Only male subjects with traumatic spinal cord injuries in the area of the 10–12th thoracic segment were included in the P group. All AB and P subjects were physically active. Mean (SE) values for age and body mass were 28 (2) years and 78.9 (3.9) kg for the AB group and 32 (4) years and 70.8 (7.9) kg for the P group (P > 0.05). Resting energy expenditure values were not found to be significantly different between AB [5.8 (0.2) kJ · min−1] and P [5.1 (0.3) kJ · min−1] subjects. Mean V˙O2peak values were 29.3 (2.4) ml · kg−1 · min−1 and 29.6 (2.2) ml · kg−1 · min−1 for the AB and P groups, respectively (P > 0.05). Absolute oxygen uptake values measured at two gas-exchange anaerobic threshold (Than) were not significantly different between the two groups. However, the Than occurred at a significantly higher percentage of V˙O2peak in the P [58.9 (1.7)%] group than in the AB [50.0 (2.8)%] group (P < 0.05). Moreover, respiratory exchange ratio (R) values obtained at the Than and at 15, 45, 60, 75 and 90 W of incremental exercise were significantly lower in the P group than in the AB group. Heart rates were significantly elevated at every submaximal work stage (15–120 W) in the P group compared to the AB group (P < 0.05). These findings suggest that chronic daily wheelchair activity produces local adaptations in the functional upper-body musculature, which reduce glycogenolysis and increase the rate of lipid utilization (lower R) during arm exercise. These local adaptations may be in part responsible for the significantly higher Than observed for arm exercise in P subjects, even though V˙O2peak values were essentially the same for both groups.

Thermoregulatory responses to exercise and warm water immersion in physically trained men with tetraplegia

Objective: To compare thermoregulatory responses of highly trained men who are tetraplegic during 40 min exercise at 65% [Vdot ]O2 peak and 60 min immersion in 39°C water.Methods: Four physically trained men who are tetraplegic participated in three laboratory visits. The first visit involved familiarisation and then determination of [Vdot ]O2 peak using open circuit spirometry during an incremental test to exhaustion with each man propelling his sport wheelchair on a motor driven treadmill. The order of second and third visits was randomly allocated. Visit 2 involved 40 min of exercise at 65% [Vdot ]O2 peak propelling each mans sport wheelchair on treadmill. Visit 3 involved sitting immersed to nipple line in 39°C water for 60 min. Venous blood was obtained pre, during and after each intervention and analyzed for haemoglobin, haematocrit and changes in plasma volume were calculated. Separated plasma was analyzed for noradrenalin and adrenalin (high performance liquid chromatography). Heart rate, rectal temperature, and sweat rate estimated from a sweat capsule placed on forehead (dew point hygrometry) were recorded throughout.Results: [Vdot ]O2 peak and HR max of these subjects were 1.14±0.16 l·min−1 and 99±4 b·min−1 respectively. Heart rate preimmersion was 67±4 b·min−1 rising to 75±4 b·min−1 after 40 min and 87±3 b·min−1 after 60 min immersion. Heart rate was 68±3 b·min−1 pre-exercise rising to 91±5 b·min−1 after 40 min exercise. Rectal temperature rose from 35.97±0.30°C pre immersion to 37.32±0.51°C after 60 min immersion, and from 36.42±0.20°C pre-exercise to 36.67±0.19°C after 40 min exercise. Haemoconcentration occurred during 40 min of exercise and haemodilution occurred throughout 60 min of water immersion. Three participants demonstrated no sweating on the forehead during immersion or exercise. One subject commenced sweating after 20 min exercise and after 5 min of immersion.Conclusion: Compared to exercise, immersion was associated with a lower heart rate, a lower plasma noradrenalin concentration and an expanded plasma volume. When considering exercise or warm water immersion as therapeutic modalities in men who are tetraplegic, attention should be paid to heat gain and changes in plasma volume.

Does endurance training affect orthostatic responses in healthy elderly men

PURPOSE To investigate the effects and time course of endurance training on the regulation of heart rate (HR), arterial pressure (AP), norepinephrine (NE), and plasma volume (PV) during orthostatic stress in healthy elderly men. METHODS Thirty-one healthy men (65--75 yr) were randomly allocated into endurance training (N = 20, EX) and control (N = 11, CON) groups. The EX group cycled 3 d x wk(-1) for 30 min at 70% VO(2peak) for 12 wk x VO(2peak) was determined on an electronically braked cycle ergometer, before training and after 4, 8, and 12 wk of endurance training. The immediate (initial 30 s), early steady-state (1 min), and prolonged (5, 10, 15 min) beat-by-beat HR and AP responses during 90 degrees head-up tilt (HUT) were measured at least 3 d after each VO(2peak) test. Spontaneous baroreflex slopes were determined by application of linear regression to sequences of at least three cardiac cycles in which systolic blood pressure (SBP) and R-R interval changed in the same direction. Venous blood was collected during 90 degrees HUT and analyzed for changes in plasma NE concentrations, as well as hematocrit and hemoglobin to determine changes in PV. RESULTS Endurance training significantly (P < 0.01) increased VO(2peak) (mL x kg(-1) x min(-1)) in EX by 10 +/- 2%. The immediate, early steady-state, and prolonged HR and AP responses and spontaneous baroreflex slopes during 90 degrees HUT were not significantly different (P > 0.05) between EX and CON groups before or after 4, 8, or 12 wk of endurance training. No significant differences (P > 0.05) were observed between EX and CON groups for peak changes in PV during orthostasis before (-15.0 +/- 1.4% vs -11.9 +/- 1.3%) or after 4 (-12.2 +/- 1.0% vs -12.7 +/- 1.4%), 8 (-13.7 +/- 1.2% vs -12.4 +/- 0.7%), and 12 wk (-10.8 +/- 1.6% vs -10.6 +/- 0.6%) of endurance training, suggesting a similar stimulus presented by 90 degrees HUT in both groups. Peak changes in NE concentrations during HUT were similar (P > 0.05) between EX and CON groups before (119 +/- 23 pg x mL(-1) vs 191 +/- 36 pg x mL(-1)) and after 4 (139 +/- 29 pg x mL(-1) vs 146 +/- 25 pg x mL(-1)), 8 (114 +/- 32 pg x mL(-1) vs 182 +/- 41 pg x mL(-1)), and 12 wk (143 +/- 35 pg x mL(-1) vs 206 +/- 42 pg.mL-1) of endurance training. CONCLUSIONS These data indicate that in healthy elderly men, improvements in VO(2peak) can occur without compromising the regulation of HR, AP, NE, and PV during orthostatic stress.

Rectal and esophageal temperatures during upper- and lower-body exercise

Abstract This study investigated the question: is core temperature measurement influenced by whether exercise involves predominantly upper- or lower-body musculature? Healthy men were allocated to three groups: treadmill ergometry (T) n=4, cycle ergometry (C) n=6 and arm crank ergometry (AC) n=5. Subjects underwent an incremental exercise test to exhaustion on an exercise-specific ergometer to determine maximum/peak oxygen consumption (V˙O2max). One week later subjects exercised for 36 min on the same ergometer at approximately 65% V˙O2max while temperatures at the rectum (Tre) and esophagus (Tes) were simultaneously measured. The V˙O2max (l · min−1) for groups T [4.76 (0.50)] and C [4.35 (0.30)] was significantly higher than that for the AC group [2.61 (0.24)]. At rest, Tre was significantly higher than Tes in all groups (P<0.05). At the end of submaximal exercise in the C group, Tre [38.32 (0.11)°C] was significantly higher than Tes [38.02 (0.12)°C, P<0.05]. No significant differences between Tre and Tes at the end of exercise were noted for AC and T groups. The temperature difference (Tdiff) between Tre and Tes was dissimilar at rest in the three groups; however, by the end of exercise Tdiff was approximately 0.2°C for each of the groups, suggesting that at the end of steady-state exercise Tre can validly be used to estimate core temperature.

Thermoregulatory responses to repeated warm water immersion in subjects who are paraplegic.

Objective: To compare thermoregulatory responses to repeated warm water immersion (39°C) between physically active subjects who are paraplegic or able-bodied in order to gain insight into rehabilitative and adaptive processes.Methods: Five paraplegic (P) and six able-bodied (AB) males participated. [Vdot ]O2 peak was determined by open-circuit spirometry using a cycle ergometer (AB) and propelling a wheelchair on a motor driven treadmill (P). Subjects sat immersed to the nipple line in 39°C water for 60 min for 5 consecutive days. Pre- and post-test measurements included heart rate (HR), oesophageal temperature (Tes), sweat onset and rate (dew point hygrometry). Venous blood was obtained before, and during immersion to estimate changes in plasma volume.Results: The P group was older and lighter than AB group (P<0.05). [Vdot ]O2max, [Vdot ]CO2max and [Vdot ]Emax were significantly greater in AB group. HR at rest and after 60 min immersion was not significantly different between the groups pre- or post-test. Tes significantly increased after 60 min immersion in both groups, at both pre- and post-testing sessions. Post-test Tes after 60 min immersion (AB) was significantly less than Tes after 60 min of immersion pre-test. The ΔTes (Tes 60 min–Tes 0 min) was significantly higher in AB group than the P group at pre- but not post-testing. No significant changes in sweat onset or rate were found for the AB or P groups during the pre- or post testing sessions. Significant expansion of plasma volume occurred during immersion in both groups, pre- and post-immersion sessions.Conclusions: Repeated warm water immersion (39°C) for 60 min per day for a total of 5 days did not produce a significant adaptive response in P group. In the AB group, Tes at the end of 60 min immersion was significantly lower after the adaptation period.Spinal Cord (2001) 39, 149–155.

Seated buttock contours: a pilot study of Australian senior high-school students

Both posture and comfort of a chair are influenced by the contour and characteristics of the seat. Knowledge of seat contours of a student population could thus be useful in the design of school chairs. This study investigated seated buttock contours of senior high-school students in order to determine: (a) their general characteristics, (b) the effect of gender and sitting posture and (c) the relationship between the contours and selected anthropometric variables (stature and mass). A contour measurement device was developed and used to measure buttock contours in five sitting postures (typing, sitting up, sitting back, slumping and writing). Buttock contours were quantified by constructing anterior–posterior (AP) and lateral profiles from which six discrete profile dimension measurements were made. AP and lateral profiles were found to have a consistent shape across all participants. Five out of six profile dimensions were significantly different between genders, with just one significantly different between sitting postures (typing and sitting back). Correlations between anthropometric measures and profile dimensions were relatively low (r < 0.34) with no clear patterns evident. Overall results of this study suggest that buttock contours are influenced by gender to a greater extent than sitting posture.

Preferred seat orientation of senior high-school students

The height of the front of the seat is the primary determinant of appropriate seat size in the school setting. In the present study, this dimension was fixed at 445 mm and, using a brief adjustment period, students adjusted the angle of the seat to their preferred rear seat height (PRSH) under three fixed and one adjustable desk height conditions and for one desk height, under two time conditions. PRSH was significantly greater at an 800 mm desk height (454±14 mm) compared to 735 mm (447±15 mm) and 720 mm (444±16 mm). When desk height as well as rear seat height were adjustable, PRSH was 446±15 mm and preferred desk height 751±25 mm. Taller students or those with larger popliteal heights selected lower PRSHs at all desk heights, with PRSH more strongly related to popliteal height (r = −0.54 to −0.59) than stature (r = −0.44 to −0.50). No differences were found in PRSH between short (<5 min) and long (30 min) adjustment periods for the 735 mm desk height. The nearly horizontal seat positions found in this study were between those recommended by other authors.