Arm Crank Ergometry - Assignment Example

Introduction: Arm crank ergometry (ACE) provides an important means by which physiological responses of individuals undertaking upper body exercisescan be examined. Much of the work within the area of ACE testing has focused upon the design of peak oxygen consumption (VO2 peak) protocols, in particular, the influence of crank rate. These studies have consistently suggested that faster crank rates serve to postpone localised muscular fatigue and result in higher peak physiological responses. However, the use of sub-maximal exercises intensities is important in individuals with coronary heart disease and other cardiopulmonary conditions, patients who present ischaemic symptoms during leg exercise and/or have painful peripheral claudication and physically disabled individuals. Previous studies have considered issues linked to exercise efficiency. This line of enquiry provides important information associated with the relationship between the energy required to achieve a given amount of external work. In the context of a competitive athlete or a patient in a clinical setting, exercise efficiency provides a useful insight into functional capacity. When presented in either gross or net terms, exercise efficiency has been shown to increase in line with workload during both cycling and ACE. Several studies have also demonstrated there to be a clear interaction between crank rate and workload with respect to oxygen consumption during cycling and ACE. Additionally, previous studies have considered exercise efficiency in a number of different ways, including the calculation of gross, net, and delta values. Powers et al. (1984) showed that VO2 during ACE increased in line with crank rate. At workloads of 15 and 30W, VO2 was lower and exercise efficiency was higher, using crank rate of 50 and 70 rev.min-1 compared to 90 rev.min-1. Furthermore, when the workloads were increased to 45 and 60W, exercise efficiency remained higher using 50 compared to 90 rev.min-1. However, Smith reported a minimal impact of crank rate on physiological responses during ACE. Mean values of VO2, minute ventilation volume (VE), heart rate (HR) and whole blood lactate concentration (BLa) were similar (p>0.05) using crank rates of 60, 70 and 80 rev.min-1 across a range of workloads (30 to 90w). Furthermore Smith et al. showed that while variations in crank rate (50, 70 and 90 rev.min-1) influenced measures of exercise efficiency a relatively low workloads (30 to 70w) during ACE, these discrepancies did not exist at 90w. These data are interesting as they question the previously reported interaction between crank rate, workload and exercise efficiency. The purpose of this practical will be to further investigate 1) if exercise efficiency parameters change in line with variations in crank rate and 2) to determine whether or mechanical efficiency varies according to the external workload being achieved. In these respects, values of gross, net and work efficiency will be considered. RESULTS. The results of the experiment are summarised in the table 1 in the Annex. You can see that the index FE02 (fractional concentration of oxygen in expired air) was varied in the range between 16.2 and 18.5 ml O2/kg/min (range is 2.3 ml O2/kg/min). Consequently the mean of 35 measurements was equal to 17.1 and its standard error is 0.09. The variance of FE02 gross value was 0.34 and standard deviation - 0.56. The distribution of the sample was asymmetric and not normal (skewness is 0.72 and kurtosis 0.29). The values of median, lower and upper quartile were equal to 17.0, 16.7 and 17.4 correspondingly. The mean value of FECO2 (fractional concentration of CO2-exhaled) was equal to 3.660.08 while the variance and standard deviation was 0.24 and 0.49 respectively. The median of the index was 3.73 and the first (lowest) and third (upper) quartiles were equal to 3.45 and 3.98 while the minimum and maximum were 2.52 and 4.44 (range is 1.92 ml CO2/kg/min). The skewness and kurtosis were not equal to zero thus the distribution was not symmetric. The data obtained for VE (ventilation volume) were following. The mean and its standard error - 28.362.26 ml/min, maximum - 61.4 ml/min, minimum - 9.4 ml/min, median - 25.9, lowest and highest quartile - 17.1 and 35.6, variance - 178.0 and standard error - 13.34 ml/min correspondingly (see table 1 in Annex). The respiratory exchange ratio (RER) values were close to 1.0. Thus the minimum value was 0.77 only whereas the maximum was 1.07 with the mean value 0.950.004. So small size of the standard error of mean could be explained with the high homogeneity of the sample and the physiological stability of the measured index. Nevertheless the distribution of the value was not symmetric (skewness = -0.68 and kurtosis - 0.57. The interesting results were determined for RPEC (rating of perceived exertion) values. The RPE-C varied between 6 and 14 with the mean 8.710.48 whereas RPE-I mean values was equal to 9.50.55. The last index assessed in the experiment was HR (heart rate). There is explicitly showed in the table 1 (see Annex) that its values varied between 73 (minimum at the rest) to 169 bpm (at the peak of physical load) with the mean 111.6 bpm and 4.79 as the standard error of mean. But the gross values are not very informative because they cannot provide the data about the dynamics and changes of the indices during the exercises. In the tables 2-5 of the Annex there are provided the descriptive statistics for different stages of the experiment. You can see that dependently on the load and time the intensity of metabolic processes is increased (see Chart 1-5 in the Annex). The chart 1 describes the changes of fractional concentration of oxygen in exhaled air. The values changing from 17.60.3 ml/ kg min in the rest to 16.70.1 on the 50th of the load. The changes of FECO2 pattern are presented on the Chart 2. You can see that in the rest this value was equal to 3.00.15 whereas the highest fractional concentrations of carbon dioxide were determined on the 50 and 75 rpm of the load - 4.10.1 and 4.00.1 ml/lg min respectively. The most significant changes were found for ventilation volume (Chart 3 in the Annex). Due to tachipnoe this value raised from 12.71.2 ml/min to 49.32.8 ml/min. However some other indices varied in more narrow ranges (Chart 4). For example RPE value varied between 0.90.04 and 1.00.01 whereas RPE-C and RPE-I have changed between 6.30.2 and 6.30.2 (minimum) 12.00.5 and 13.10.3 (maximum) correspondingly. Heart rate (HR) was varied in the range 86.74.6 bpm (rest) and 1495.6 bpm (75 rpm). Thus the response of cardiovascular system was proportional to the physical load. General efficiency, net efficiency and work efficiency were assessed as the ratio of kcal/min equivalent of power output to kcal/min of total energy expended, energy expended above rest and energy expended above unloaded exercise, respectively. DISCUSSION. These results are similar to the reports of other authors. Thus Goosey-Tolfrey & Sindall (2007) described the physiological responses and indices of mechanical efficiency between asynchronous and synchronous arm ergometry. In their study mechanical efficiency indices - gross efficiency and net efficiency were equal to 16.92.0% (60 W) and 14.72.4% (80W) and 17.51.8% (60W) vs. 15.92.6% (80W) respectively. Authors have not found any differences in heart rate, blood lactate concentration or power output at either of the blood lactate reference points between the asynchronous and synchronous arm crank ergometry. Another recently published article (Smith et al., 2006) devoted to the effects of ramp rate on VO2-peak and "excess" VO2 during arm crank ergometry. British scientists examined how different ramp rates influenced the attainment of peak physiological responses during incremental arm crank ergometry (ACE). They found that differences in ramp rate within the range of 6 - 12 W/min influence the peak values of work rate, VCO2 and RER, but do not influence peak values of VO2 or HR during arm crank ergometry. Other research of these authors describes the results of the experiment on the influence of crank rate on the slow component of pulmonary oxygen uptake during heavy arm-crank exercise. They consider the possibility of greater contribution of "low-efficiency" type II muscle fibres to force production at the lower crank rate releted ti the differences in muscle tension. In our experiment the changes of FEO2 and FECO2 were reciprocal - with the increase of exhaled CO2 the values of fractional concentration of CO2-exhaled are decreased. Taylor & Bronks (1996) did not find any differences in gas exchange variables at rest (VO2 VE RR, VT) and submaximal work. Smith, Doherty & Price (2007) also examined the effects of variations in crank rate on physiological responses during submaximal arm ergometry. They confirmed the role of the variations in crank rate in influencing gross and net values of V(O2) and exercise efficiency at low absolute workloads. The authors urgued that crank rate also is an influential factor at moderate workloads. You can see from the Charts 1-5 (see Annex) that VE, RER, RPE-C, RPE-I and HR depend on the duration of physical load. The highest delta for these parameters was determined for the 25th and 50th seconds of the load. Dallmeijer et al. provided similar data (2004). Their study determined the highest difference between synchronous and asynchronous hand cycling at 84 vs. 65 rpm and at 36 vs. 47 rpm. The authors determined that synchronous hand cycling (used in our experiment) is less strenuous and more efficient than asynchronous one. French specialists from the Universite de Lille (Dekerle et al., 2002) paid the attention to the problem of the dependence of the first and the second ventilatory thresholds (VT1 and VT2) on the muscle groups and crank and pedal rates. This study demonstrated the absolute oxygen uptake (VO2) values measured at sub-maximal and at maximal workload were significantly different during arm and leg exercises. Similar data were obtained by Marais et al. (2002). Their research was aimed to compare the physiological responses during arm exercises during the different crank rate. Authors consider that crank rates lower than spontaneous crank rate increase gross efficiency. However in our experiment (see Tables 1-6 in the Annex) this supposition was not approved. The absence of the significant differences between the different crank rates could be explained by the small size of the sample nevertheless there is expediently to conduct further studies on this issue. Smith, Price & Doherty (2001) assessed the influence of the different crank rates on the attainment of peak oxygen consumption (VO2peak) and other physiological responses during incremental arm crank ergometry. Similarly to other research conducted by Smith (2001) its results demonstrated the greater physiological responses observed during the tests at faster crank rates might have been the result of a postponement of acute localized neuromuscular fatigue. Authors recommend that an imposed crank rate between 70 and 80 rev x min(-1) should be used to elicit VO2peak and other physiological responses in arm crank ergometry. However van der Woude et al. (2000) wrote about other results in the article devoted to the discussion of the various modes of hand cycling. The authors found that significantly lower levels of mean oxygen uptake, ventilation, relative heart rate and oxygen uptake occur during synchronic ACE with the higher crank rate. Marais et al. (1999) described the physiological effects of variations in spontaneously chosen crank rate during sub-maximal and supra-maximal upper body exercises. Their findings demonstrated that upper body exercise performed on an ergocycle should be conducted using the freely and spontaneously chosen crank rate. Interesting data were provided by Birkett & Edwards (1998) from Oxford Brookes University. They found that heart rate and Vo2 were highly correlated and the data obtained during one-arm sub-maximal cranking are useful for assessing an individual's aerobic capacity. Weissland et al. (1997) conducted the clinical trial aimed to assess the inter-individual variations of a spontaneously chosen crank rate (SCCR) in relation to the power developed during an incremental upper body exercise on an arm ergometer set at a constant power regime, and to compare heart rate responses, expired minute ventilation and oxygen consumption for the different pedal rates. In this study there was demonstrated that the increase in heart rate, ventilation volume and oxygen consumption correlate to the increase of the physical load. Our experiment was conducted on the healthy young males but many authors (Goosey-Tolfrey et al. (2006), Sutbeyaz, Koseoglu & Gokkaya (2005), Jacobs et al. (2005), Sedlock et al. (2004, Koppo, Bouckaert & Jones 2002, Smith, Price & Doherty (2001), Lassau-Wray & Ward (2000), Mossberg et al. (1999), Mercier B et al. (1993, Drory et al. (1990) etc) discuss the issues of ACE amongst the patients suffering chronic diseases (e.g. neurological disorders, cardiovascular problems, posttraumatic conditions so on). The similarity of the results published in these articles demonstrate the universal character of the physiological reaction for physical efforts and allow to use ACE as a tool of diagnostics and medical rehabilitation. CONCLUSION. The experimental data showed that exercise efficiency parameters change are in the direct proportion with variations in crank rate - they are increased with the increase of crank rate and decreased when the frequency of rotations are lower. We determined that mechanical efficiency varies according to the external workload. Thus values of gross, net and work efficiency were higher for increased crank rate. The results of the experiment are correlated with the previous reports available in the modern clinical and physiological journals. References: 1. Birkett & Edwards (1998) The use of one-arm crank ergometry in the prediction of upper body aerobic capacity. Clinical Rehabilitation. Vol. 12(4) pp. 319-327. 2. Dallmeijer et al. (2004) A physiological comparison of synchronous and asynchronous hand cycling. International Journal of Sports Medicine. 2004 Vol. 25(8) pp. 622-626. 3. Dekerle et al. (2002) Ventilatory thresholds in arm and leg exercises with spontaneously chosen crank and pedal rates. Perception and Motor Skills. Vol. 95(3 Pt 2) pp. 1035-1046. 4. Drory et al. (1990) Arm crank ergometry in chronic spinal cord injured patients. Archives of Physical Medicine and Rehabilitation. Vol. 71(6) pp. 389-392. 5. Goosey-Tolfrey & Sindall (2007) The effects of arm crank strategy on physiological responses and mechanical efficiency during submaximal exercise. Journal of Sports Science. Vol. 25(4) pp. 453-460. 6. Goosey-Tolfrey et al. (2006) Aerobic capacity and peak power output of elite quadriplegic games players. British Journal Sports Medicine. Vol. 40(8) pp. 684-687. 7. Hooker et al. (1993) Influence of posture on arm exercise tolerance and physiologic responses in persons with spinal cord injured paraplegia. European Journal of Applied Physiology and Occupational Physiology. Vol. 67(6) pp. 563-566. 8. Hooker et al. (1993) Oxygen uptake and heart rate relationship in persons with spinal cord injury. Med Sci Sports Exerc. Vol. 25(10) pp. 1115-1119. 9. Jacobs et al. (2005) Reliability of upper extremity anaerobic power assessment in persons with tetraplegia. Journal of Spinal Cord Medicine. Vol 28, No. 2 pp. 109-113. 10. Koppo, Bouckaert & Jones (2002) Oxygen uptake kinetics during high-intensity arm and leg exercise. Respiratory Physiolpgy and Neurobiology. Vol. 133(3) pp. 241-250. 11. Lassau-Wray & Ward (2000) Varying physiological response to arm-crank exercise in specific spinal injuries. Journal of Physiology, Anthropology and Applied Human Science. 2000 Vol. 19(1) pp. 5-12. 12. Louhevaara et al. (1990) Differences in cardiorespiratory responses during and after arm crank and cycle exercise. Acta Physiologica Scandinavica. Vol. 138(2) pp. 133-143. 13. Marais et al. (1999) Physiological effects of variations in spontaneously chosen crank rate during sub-maximal and supra-maximal upper body exercises. International Journal of Sports Medicine. Vol. 20(4) pp. 239-245. 14. Marais et al. (2001) RPE responses during arm and leg exercises: effect of variations in spontaneously chosen crank rate. Perception and Motor Skills. Vol. 92(1) pp. 253-262. 15. Marais et al. (2002) Spontaneously chosen crank rate variations in submaximal arm exercise with inexperienced subjects. Effects on cardiorespiratory and efficiency parameters. International Journal of Sports Medicine. Vol. 23, 2 pp. 120-124. 16. McConnell et al. (1989) Arm crank versus wheelchair treadmill ergometry to evaluate the performance of paraplegics. Paraplegia. 1989 Vol. 27(4) pp. 307-313. 17. Mercier et al. (1993) Anaerobic and aerobic components during arm-crank exercise in sprint and middle-distance swimmers. European Journal of Applied Physiology and Occupational Physiology. Vol. 66(5) pp. 461-466. 18. Mossberg et al. (1999) Comparison of asynchronous versus synchronous arm crank ergometry. Spinal Cord. Vol. 37(8) pp. 569-574. 19. Sedlock et al. (2004) Excess post-exercise oxygen consumption in spinal cord-injured men. European Journal of Applied Physiology. Vol. 93(1-2) pp. 231-236 20. Sedlock, Knowlton & Fitzgerald (1990) Circulatory and metabolic responses of women to arm crank and wheelchair ergometry. Archives of Physical Medicine and Rehabilitation. Vol. 71(2) pp. 97-100. 21. Smith et al. (2004) The influence of step and ramp type protocols on the attainment of peak physiological responses during arm crank ergometry. International Journal of Sports Medicine. Vol. 25(8) pp. 616-621. 22. Smith et al. (2006) Influence of crank rate on the slow component of pulmonary O(2) uptake during heavy arm-crank exercise. Applied Physiology, Nutrition and Metabolism. Vol. 31(3) pp. 292-301. 23. Smith et al. (2006) The influence of ramp rate on VO2peak and "excess" VO2 during arm crank ergometry. International Journal of Sports Medicine. Vol. 27(8) pp. 610-616. 24. Smith, Doherty & Price (2006) The effect of crank rate on physiological responses and exercise efficiency using a range of submaximal workloads during arm crank ergometry. International Journal of Sports Medicine. Vol. 27(3) pp. 199-204. 25. Smith, Price & Doherty (2001) The influence of crank rate on peak oxygen consumption during arm crank ergometry. Journal of Sports Science. Vol. 19(12) pp. 955-960. 26. Sutbeyaz, Koseoglu & Gokkaya (2005) The combined effects of controlled breathing techniques and ventilatory and upper extremity muscle exercise on cardiopulmonary responses in patients with spinal cord injury. // Int J Rehabil Res. Vol. 28(3) pp. 273-276. 27. Taylor & Bronks (1996) An on-demand system of delivering pre-mixed inspiratory gas for use during physical activity. Australian Journal of Science and Medicine in Sport. Vol. 28(3) pp. 76-78. 28. van der Woude et al. (1993) Physiological evaluation of a newly designed lever mechanism for wheelchairs. Journal of Medical Engineering Technology. Vol. 17(6) pp. 232-240. 29. van der Woude et al. (2000) Handcycling: different modes and gear ratios. Journal of Medical Engineering Technology. Vol. 24(6) pp. 242-249. 30. Weissland et al. (1997) Physiological effects of variations in spontaneously chosen crank rate during incremental upper-body exercise. European Journal of Applied Physiology and Occupational Physiology. Vol. 76(5) pp. 428-433. Annex Table 1. Descriptive statistics of the experiment Valid N Mean Median Minimum Maximum Lower Quartile Upper Quartile Range Variance Std.Dev. Standard Error Skewness Kurtosis FE02 35 17.1 17 16.2 18.5 16.7 17.4 2.3 0.34 0.56 0.09 0.72 0.29 FECO2 35 3.66 3.73 2.52 4.44 3.45 3.98 1.92 0.24 0.49 0.08 -0.59 -0.15 VE 35 28.36 25.9 9.4 61.4 17.1 35.6 52 178.0 13.34 2.26 0.70 -0.04 RER 34 0.95 0.955 0.77 1.07 0.92 0.99 0.3 0.004 0.06 0.01 -0.68 0.57 RPEC 28 8.71 8 6 14 6 11 8 6.36 2.52 0.48 0.48 -1.05 RPEI 28 9.5 9.5 6 14 7 12 8 8.41 2.9 0.55 0.12 -1.62 HR 35 111.6 111 73 169 88 139 96 801.72 28.3 4.79 0.36 -0.98 Table 2. Descriptive statictics at the stage of rest Valid N Mean Median Minimum Maximum Lower Quartile Upper Quartile Range Variance Std.Dev. Standard Error Skewness Kurtosis FE02 7 17.6 17.8 16.7 18.5 16.8 18.3 1.8 0.5 0.7 0.26 -0.29 -1.2 FECO2 7 3.0 2.9 2.52 3.53 2.67 3.46 1.01 0.2 0.4 0.15 0.02 -2.0 VE 7 12.7 11.4 9.4 17.1 9.65 16.7 7.7 10.8 3.3 1.24 0.48 -1.9 RER 6 0.9 0.9 0.84 1.07 0.85 1.02 0.23 0.01 0.1 0.04 0.14 -1.6 RPEC 0 -- -- -- -- -- -- -- -- -- -- -- -- RPEI 0 -- -- -- -- -- -- -- -- -- -- -- -- HR 7 86.7 82 73 104 76 99 31 147.9 12.2 4.60 0.39 -1.8 Table 3. Descriptive statistics at the 0 stage Valid N Mean Median Minimum Maximum Lower Quartile Upper Quartile Range Variance Std.Dev. Standard Error Skewness Kurtosis FE02 7 17.2 17.3 16.4 18.1 16.8 17.6 1.7 0.3 0.5 0.2 -0.01 0.4 FECO2 7 3.5 3.5 2.85 3.96 3.1 3.67 1.11 0.14 0.37 0.1 -0.03 -0.30 VE 7 21.4 19.4 16.3 29.3 17.1 25.9 13 23.6 4.9 1.8 0.7 -0.9 RER 7 0.9 0.95 0.77 0.99 0.88 0.97 0.22 0.005 0.07 0.03 -1.57 2.6 RPEC 7 6.3 6 6 7 6 7 1 0.2 0.5 0.2 1.2 -0.8 RPEI 7 6.3 6 6 7 6 7 1 0.2 0.5 0.2 1.2 -0.8 HR 7 95.6 88 74 117 83 114 43 271.0 16.5 6.2 0.2 -1.7 Table 4. Descriptive statistics at stage of 25 Valid N Mean Median Minimum Maximum Lower Quartile Upper Quartile Range Variance Std.Dev. Standard Error Skewness Kurtosis FE02 7 16.9 16.9 16.4 17.3 16.5 17.2 0.9 0.1 0.4 0.1 -0.2 -1.7 FECO2 7 3.8 3.8 3.45 4.08 3.65 3.92 0.63 0.04 0.21 0.08 -0.4 0.2 VE 7 25.6 24.8 22.5 32.9 22.5 26.7 10.4 13.6 3.7 1.4 1.5 2.4 RER 7 0.9 0.93 0.86 0.99 0.87 0.97 0.13 0.002 0.05 0.02 -0.2 -1.5 RPEC 7 6.9 7 6 8 6 8 2 0.8 0.9 0.3 0.35 -1.82 RPEI 7 7.4 7 6 9 7 8 3 0.95 0.9759 0.37 0.28 0.04 HR 7 101.7 94 73 140 77 119 67 582.6 24.1 9.1 0.40 -0.8 Table 5. Descriptive statistics at the stage of 50th Valid N Mean Median Minimum Maximum Lower Quartile Upper Quartile Range Variance Std.Dev. Standard Error Skewness Kurtosis FE02 7 16.7 16.9 16.2 17.1 16.3 17 0.9 0.13 0.4 0.1 -0.4 -1.9 FECO2 7 4.1 4.01 3.73 4.44 3.94 4.43 0.71 0.07 0.3 0.1 0.5 -0.7 VE 7 32.8 31.9 25.9 39.7 31.4 35.6 13.8 17.9 4.2 1.6 0.08 1.3 RER 7 0.96 0.95 0.9 1.02 0.92 1 0.12 0.002 0.05 0.02 0.08 -2.0 RPEC 7 9.7 10 8 11 9 11 3 1.2 1.1 0.4 -0.2 -0.9 RPEI 7 11.1 11 10 12 11 12 2 0.5 0.7 0.3 -0.2 0.3 HR 7 125 116 103 152 111 141 49 347.7 18.6 7.0 0.4 -1.8 Table 6. Descriptive statistics at the stage of 75th Valid N Mean Median Minimum Maximum Lower Quartile Upper Quartile Range Variance Std.Dev. Standard Error Skewness Kurtosis FE02 7 17.0 17 16.5 17.4 16.6 17.4 0.9 0.1 0.4 0.1 -0.2 -1.3 FECO2 7 4.0 3.97 3.54 4.31 3.63 4.27 0.77 0.09 0.3 0.1 -0.3 -1.7 VE 7 49.3 49.2 41.6 61.4 42.1 55.1 19.8 55.4 7.4 2.8 0.5 -0.9 RER 7 1.0 0.99 0.95 1.03 0.97 1.03 0.08 0.001 0.03 0.01 -0.3 -1.3 RPEC 7 12 12 10 14 11 13 4 1.7 1.3 0.5 0 0.3 RPEI 7 13.1 13 12 14 13 14 2 0.5 0.7 0.3 -0.2 0.3 HR 7 149 147 127 169 136 161 42 216.3 14.7 5.6 -0.2 -0.9 Chart 1. The dynamics of FEO2 value Chart 2. The dynamics of FECO2 value Chart 3. The dynamics of VE value Chart 4. The dynamics of RER value Chart 5. The dynamics of RPE-C and RPE-I values Chart 5. The dynamics of heart rate Read More