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The use of regression equations to predict oxygen uptake in relation to speed, grade, power output, and anthropometric characteristics is common in cardiac rehabilitation and athlete fitness testing. Research has suggested that sport specific testing improves the reliability of the test methodology and is appropriate for the development of effective training programs. This study focused on the development of a cross-country skiing specific predictor of maximal oxygen uptake based on treadmill speed, treadmill grade, gender, and body mass. This project simulated snow skiing on a large research treadmill using roller skis. A small sample size (N = 34) warranted the use of bootstrapping techniques and multiple regression analysis to develop a cross-country skiing specific model of oxygen uptake. The stability of each bootstrapped sample was confirmed via a cross-validation procedure. The equation of best resolve was: VO2 = -4.534 + 0.223(G) + 0.061(BM) + 0.139(TG) + 0.016(TS) in which G = Gender, BM = Body Mass, TG = Treadmill Grade, TS = Treadmill Speed. The resultant model can be used to design training programs, develop athlete fitness testing or research protocols, and to predict maximal oxygen uptake when sophisticated metabolic measurement equipment is unavailable. [ABSTRACT FROM AUTHOR] more...

The nature and degree of fatigue in muscles that control finger position during repeated sustained efforts in rock climbing have not been described. The purpose of this study was to identify changes in maximum hang time and forearm electromyogram (EMG) during repeated maximum duration hangs from a simulated rock feature. A second objective was to determine the effect of different recovery times between hangs upon changes in finger force. Five experienced rock climbers performed 2 test sessions on different days in a randomized order. Each session involved 8 repetitions of a maximum duration hang with either 1 min (R1) or 3 min (R3) resting recovery between hangs. Finger force (FF) was measured for the right hand via a piezoelectric force sensor fitted with a plate to accept the distal digits of four fingers. Peak EMG (EMGPK) and EMG Area (EMGAREA) were recorded from the anterior forearm for each hang and standardized as percent of maximum FF EMG prior to statistical analysis. Hang duration progressively decreased over repetitions but tended to plateau around repetition 5 for both R1 and R3 conditions. A significant difference was found for both recovery conditions and repetitions (p<.05) as well as a significant interaction of the two factors (p<.05) for hang duration. There were no significant differences for EMGPK among repetitions or between recovery conditions (p>.05). EMGAREA decreased initially with repeated hangs during both R1 and R3 but this trend tended to plateau at repetition 3 for the R3 condition. A significant difference was found in EMGAREA for both recovery conditions and trials (p<.05) as well as a significant interaction of the two factors (p<.05). Mean FF decreased between pre- and post-hangs for both R1 and R3 however the difference was not significant. It was concluded that the overall decline in hang time is less with 3 min recovery vs 1 min recovery between hangs. Peak EMG does not appear to change despite this evidence of fatigue. A 3 min recovery interval between hang repetitions decreases the magnitude of fatigue experienced and enables a greater EMGAREA per hang. [ABSTRACT FROM AUTHOR] more...

Int J Exerc Sci 1(1): 4-13, 2008 Handgrip dynamometry is often given importance in the study of rock climbing performance. Whether handgrip dynamometry produces a degree of muscle activation comparable to actual climbing has not been reported. Furthermore, the degree and variability of muscle activation for various hand configurations during climbing are unknown. The purpose of this study was to record forearm EMG responses for six hand configurations during climbing and to compare these responses to a maximum handgrip test. Five experienced climbers performed four moves up (UP) and down (DN) on an overhanging 45-deg. climbing wall with each of six hand configurations: crimp (C), pinch (P), three 2-finger combinations (2F1, 2F2, 2F3) and an open-hand grip (O). Forearm EMG was recorded via surface electrodes. Data were recorded for the second UP and second DN moves. Prior to climbing, maximum handgrip force (HG) and simultaneous EMG were obtained. Mean HG force was 526.6±33.3 N. Times to complete the climbing movements with each hand configuration varied between 3.1±0.5 and 4.8±0.9 sec with no significant differences. Peak EMG's during climbing were higher than HG EMG (p<.05). Mean EMG amplitudes for UP, as percentages of HG EMG, were 198±55, 169±22, 222±72, 181±39, 126±32, and 143±47% for C, P, 2F1, 2F2, 2F3, and O respectively. Significant differences were found for O versus 2F1 and for 2F3 versus 2F1 and C (p<.05). EMG amplitudes were lower for DN than UP (p<.05). Since all climbing EMGs exceeded HG EMG, it was concluded that handgrip dynamometry lacks specificity to actual rock climbing. [ABSTRACT FROM AUTHOR] more...

Examines the reliability of peak isometric force during curl-ups among 50- to 84-year-old individuals. Use of a calibrated force plate to measure pulling; Factors that complicate the assessment of abdominal muscle strength; Procedures on the correct execution of curl-ups. more...

To examine the reliability for peak responses of oxygen consumption (VO[SUB2peak]) in relative (ml · kg[SUP-1] · min[SUP-1]) and absolute (L/min[SUP-1]) measures, as well as peak heart rate (HR[SUBpeak]) during deep water running (DWR), 26 participants (12 women, 14 men) completed two DWR maximal graded exercise tests. To estimate the validity of the peak responses during DWR, a comparison to a treadmill running (TMR) graded exercise test (GXT) was completed. Test order was randomized. The DWR GXT utilized a system of weights and pulleys to increase intensity of exercise. Reliability of the DWR test for the total group was estimated using a repeated measures one-way analysis of variance (ANOVA) for VO[SUB2peak] (ml · kg[SUP-1] · min[SUP-1], R = .96; L/min[SUP-1], R = .97) and HR[SUBpeak] (R = .90). There were no significant differences (p > .05) between the two DWR tests for men or women for the means of VO[SUB2peak] in relative units (men: 50.5 vs. 52.0 ml · kg[SUP-1] · min[SUP-1]; women: 37.1 vs. 36.8 ml · kg[SUP-1] · min[SUP-1]), or absolute units (men: 4.1 vs. 4.1 L/min[SUP-1]; women: 2.2 vs. 2.2 L/min[SUP-1]), or HR (men: 174 vs. 175 beats per minute (bpm); women: 181 vs. 183 bpm). There was a significant correlation between the average of the two DWR tests and TMR for the total group for VO[SUB2peak] for relative (r = .88, p = .001) and absolute (r = .93, p = .001) measures as well as HR[SUBpeak] (r = .64, p = .001). Peak responses during the DWR protocol were judged to be reliable. Also, the correlation for the variables between DWR and TMR indicates a positive relation between peak responses. The correlation suggests validity of predicting TMR peak responses from DWR peak responses; however, this conclusion may be questionable due to the low sample size and the large systemic differences between tests. Finally, HR[SUBpeak] and VO[SUB2peak] were lower during DWR than TMR for both men and women. [ABSTRACT FROM AUTHOR] more...

This study examined the effects of cycling posture on subsequent running performance similar to the transition phase of a triathlon. Experienced, non-elite triathletes completed two trials of a cycle-run transition. During the last three minutes of a 30 minute cycling bout, at power output equal to lactate threshold, subjects either remained seated (SEAT), or alternated seated and standing cycling (30 s at a time; ALT). Heart rate, RPE, minimum and maximum knee angle, stride frequency and length, and onset and duration of quadriceps and hamstrings activity were obtained at the end of a three-minute control run and at minutes 0, 2, & 4, of running after cycling transition. Repeated Measures ANOVA (condition X minute; p = 0.05) found control was significantly different than minute 0 for stride frequency and length, but not for minimum or maximum knee angle. EMG duration at minute 4 was less than all other time points for both quadriceps and hamstrings. Onset of muscle activity was not different for hamstring or quadriceps. Heart rate and RPE both increased over 15 minutes after transition and were higher for SEAT than ALT, however, there was no interaction (minute by position) for either variable. Results indicated changes in stride rate and length following cycling occur, but disappear within two minutes after the transition to running and do not differ between postures. Changes in duration of muscle activity may be related to changes in stride. Also HR and RPE differ between the SEAT and ALT cycling positions and over time. more...