Trekking poles are becoming increasingly popular for recreational hikers. However, very little is know regarding the effects of pole use on gait kinematics. PURPOSE To document the effects of bilateral trekking poles on joint kinematics and several stride variables. METHODS After obtaining university-approved informed consent, 10 men and 7 women (age = 22.8 ± 2.5 yrs, height = 1.74 ± 0.09 m, mass = 69.3 ± 11.7 kg), all novice pole users, were recruited to walk at a self-selected pace for 12 trials, after gaining familiarity with proper pole use, across three walkways ∼ 23 m in length. Participants walked two times each with and without trekking poles over level, downhill, and uphill conditions (slope = 7%), in that order. Sagittal plane kinematics were videotaped at 60 Hz. Reflective markers were digitized for one complete stride to determine maximum, minimum, and average joint angles of both the upper and lower extremities. Statistical significance was set at p < 0.10. RESULTS For all walking conditions there was a significant increase in stride length, stride time, elbow flexion, ulnar deviation at the wrist, and hip flexion with pole use. In level and downhill conditions, pole use elicited a significant decrease in overall walking speed. Anterior tilt of the torso significantly increased in the uphill and level conditions with pole use. CONCLUSION Trekking poles alter several gait characteristics. The altered kinematics may increase fatigue for the novice user if utilized for an extended period of time. Further investigation is needed regarding long-term pole use and adaptations of gait.

329 The purpose of this study was to determine the energy expenditure of females during recreational snowshoeing and to assess the validity of HR-VO2 regression equations in predicting energy expenditure. Subjects(n=7) performed three exercise protocols: one maximal stress test, and two steady state protocols [treadmill speed (3.2, 4.8, 6.4 kmph) and grade (3, 6, 9%) were varied to ascertain the HR-VO2 regression equation which would give the most accurate prediction of VO2 in the field] on a treadmill. Subjects then snowshoed [walking] for a total of 30 minutes on uphill and downhill grades. Each subjects' VO2 in L·min-1 and ml·kg-1min-1, RER, HR, ECO2%, EO2%, and VEs were measured with the AeroSport KBI-C (AeroSport, Inc., Ann Arbor, MI). Energy expenditure for snowshoeing uphill was found to average 7.8±1.8 kcals/min. Downhill data determined that energy expenditure was less with a group mean of 5.5±1.3 kcals/min. Mean VO2 on an uphill grade and downhill grade averaged 63% and 44% of maximal VO2, respectively. Mean HR while snowshoeing uphill was at 80% of maximal and 68% of maximal while downhill snowshoeing. A repeated measures ANOVA was run to compare estimated VO2 in each regression equation to the VO2 as measured by the Aerosport KB1-C. Estimated uphill VO2 in each equation compared to actual values showed no significant difference among groups. Downhill VO2 estimations and actual values revealed significance F(3,18)=3.44, p=.039, accounting for 14% of the treatment effect (ω2), between actual VO2 and the HR-VO2 max regression and the grade-dependent steady state regression. Mean HR values for uphill and downhill were found to fall within the target heart zone established by the American College of Sports Medicine. Therefore, it is concluded that snowshoeing is an activity that can be utilized to achieve or maintain cardiovascular fitness.

320 The purpose of this study was to determine the energy expenditure of recreational skiers on groomed and ungroomed terrain. The applicability of applying a HR-VO2 regression to the sport of downhill skiing was also evaluated. Subjects (n=7) were given a maximum stress test on the first test session; and the second test consisted of skiing alternately, in a randomly selected order, one intermediate level groomed run, one intermediate level ungroomed run, and one advanced level ungroomed run, for a total of 3 runs. Both tests were conducted at base elevation 2895m with a summit elevation of 3780m. Each subjects' VO2 in L·min-1 and ml·kg-1min-1, RER, heart rate (HR), ECO2%, EO2%, and VEs were measured with the AeroSport KBI-C (AeroSport, Inc., Ann Arbor, MI). A repeated measures ANOVA compared VO2 and HR for each of the three runs of increasing difficulty. The VO2(ml·kg-1min-1) calculated for the intermediate-groomed run (17.5±2.0) was lower than both the intermediate-ungroomed(22.9±3.0) and the advanced-ungroomed run (23.2±4.7), accounting for 41% of the treatment effect (ω2). HR was significantly lower in the intermediate-groomed run (141±22) compared to the intermediate-ungroomed run (151±15) and the advanced-ungroomed run(157±14), accounting for 63% of the treatment effect (ω2). HR-VO2 regressions were calculated for each individual from their maximal stress test data. Significant differences occurred between the regression VO2 values and the actual VO2 values; with the regression values overpredicting the actual values. As expected, caloric expenditure increased with respect to the difficulty of the slope. Average energy expenditure for the intermediate-groomed run was 6.2±2.0 kcal/min, the intermediate-ungroomed run was 10.9±2.1 kcal/min and the advanced-ungroomed run was 1.3±2.5 kcal/min. These data suggest that a high energy expenditure occurs while participating in alpine skiing on ungroomed runs.

711 The purpose of this study was to determine the validity of the AeroSport KB1-C (AS) (AeroSport, Inc., Ann Arbor, MI) as compared to the the SensorMedics 2900 metabolic cart (SM) (SensorMedics, Yorba Linda, CA). Subjects (n=10) performed a maximal graded treadmill test with three steady state stages. Each subjects' oxygen consumption (VO2), percent expired carbon dioxide (%CO2), percent expired oxygen (%O2), and ventilation (VE) were measured with both the AS and SM. Independent groups t-tests compared differences on data collected at the end of the first 3 stages and maximum capacity. Mean values are reported in the following table.TableThere were no significant differences in any values at the end of stages 1-3 or at maximum capacity. Consistency was demonstrated for the AS with the SM system as evidenced with a moderate correlation for%CO2 (.52) and high relationships for VO2 (.94),%O2 (.88), and VE (.98). In conclusion, AS provides similar VO2,%CO2,%O2, and VE values to those measured by the SM system.

The purpose of this study was to determine the utility of the TriTrac-R3D as a valid instrument in the estimation of energy expenditure (EE) as compared to the Aerosport TEEM 100 Metabolic Analysis System. The data storage capability of the TriTrac allows for the long-term estimation of EE. The TriTrac monitors physical activity in movement counts and converts these via software (v2.03) into kcals/min. Prior to the field tests, the subject underwent a maximal stress test to validate the Aerosport with the SensorMedics 2900 metabolic cart. Subsequently, a HR-VO2 regression was developed for backpacking by submaximal treadmill testing with the subject wearing a backpack loaded to 20kg (25% of body weight). The subject hiked in the field wearing the same backpack load on ten different days in order to establish the validity of the TriTrac. Each of these ten hikes were on a measured, level gradient, outdoor course with the subject hiking for one hour at normal walking gait (3 mph) with the Aerosport carried in the backpack. The mean kcals/min (6.39±.69) calculated from the Aerosport VO2 during the field tests was significantly different from the TriTrac kcals/min(5.32±.50) [t(9)=3.32, p=.009]. A 2-day field study at Grand Canyon National Park revealed a significant difference [t(212)=8.34, p<.001] between the mean kcals/min (5.51±1.51) calculated from the HR-VO2 regression equation with the TriTrac kcals/min(4.47±1.02) when hiking down grade. There was also a significant difference [t(254) = 28.91, p<.001] between the HR-VO2 kcals/min(10.39±3.32) and the TriTrac kcals/min (4.14±.78) for the hike back up. Thus, the TriTrac underestimated EE in every instance, and did not distinguish between uphill and downhill hiking.

The purpose of this study was to assess energy expenditure (EE) during a two-day backpacking excursion. The subject underwent a maximal treadmill stress test to establish maximal HR and VO2, and to validate the Polar Vantage XL HR monitor and the Aerosport TEEM 100 metabolic analyzer with the SensorMedics 2900 metabolic cart. Subsequently, a HR-VO2 regression was developed for backpacking by submaximal testing. The subject hiked on the treadmill wearing a backpack loaded to 20kg (25% of body weight). Treadmill speed (2, 3, 4 mph) and grade (0.0, 2.5, 5, 7.5, 10, 12.5, 15%) were tested on subsequent days to ascertain the HR-VO2 regression equation which would give the most accurate prediction of VO2 in the field. The regression equations were validated in the field by backpacking one hour on the level at 3 mph, six different times. VO2 was measured directly with the Teem 100 and compared to VO2 values from the HR-VO2 regression equations. In spite of differing climatic conditions across trials both HR regression equations remained valid. The site of the two-day field study was Grand Canyon National Park. Trails were selected to allow for a days backpacking on a downward gradient and then a days backpacking on an uphill gradient. The average VO2 while hiking uphill was calculated as 49% VO2max(9.85 kcal/min) and reached as high as 71%. While hiking downhill the average VO2 was calculated as 28% VO2max (5.64 kcal/min) and reached as high as 58%. The analysis of EE demonstrated variability relating to gradient and uncontrolled climatic conditions: caloric expenditure fluctuated with respect to the difficulty of the terrain (switchbacks vs. steps), temperature, and speed of the hiking gait. In summary, this study demonstrates that the use of a HR monitor in association with the HR-VO2 regression equation determined on the treadmill provides useful data on VO2 and EE during multi-day recreational backpacking.