1 00:00:00,886 --> 00:00:02,576 My name is Sarah Wilkinson. 2 00:00:02,583 --> 00:00:04,619 This is the second of the video series 3 00:00:04,619 --> 00:00:07,535 showing how to convert VO2 values. 4 00:00:08,159 --> 00:00:10,891 In this video I am going to show you how to 5 00:00:11,109 --> 00:00:14,962 easily convert a relative VO2 value to an 6 00:00:15,112 --> 00:00:16,651 absolute VO2 value. 7 00:00:16,842 --> 00:00:19,656 Please make sure you have watched the first video 8 00:00:19,793 --> 00:00:22,917 which shows you the basic mathematical principle 9 00:00:23,045 --> 00:00:26,045 I am using to do these conversion factors. 10 00:00:26,201 --> 00:00:30,087 As a well as a little background of what VO2 is. 11 00:00:30,427 --> 00:00:36,254 In this video I am going to show you how to 12 00:00:36,409 --> 00:00:38,849 convert a relative VO2 value, 13 00:00:38,979 --> 00:00:43,108 which is measured in ml per kg body mass per minute 14 00:00:43,253 --> 00:00:47,163 to an absolute value, in litres per minute. 15 00:00:47,285 --> 00:00:52,073 I am going to set it up by putting my relative value on the left hand side 16 00:00:52,196 --> 00:00:56,483 and on the far right hand side, I have put in 17 00:00:56,702 --> 00:00:58,175 what I am trying to convert to, 18 00:00:58,296 --> 00:01:01,709 so the absolute value of L per minute. 19 00:01:01,865 --> 00:01:05,248 Let's use a theoretical example, and say we have 20 00:01:05,341 --> 00:01:07,843 someone with a VO2max of 21 00:01:07,974 --> 00:01:12,040 45 ml of oxygen per kilogram body mass per minute 22 00:01:12,202 --> 00:01:17,389 This is essentially 45 ml per 1kg minute. 23 00:01:17,529 --> 00:01:18,793 Normally we don't put the '1' in. 24 00:01:18,917 --> 00:01:20,928 Just to show you what should be on the denominator. 25 00:01:21,078 --> 00:01:24,682 I need to do two conversions factors. 26 00:01:24,812 --> 00:01:28,124 I need to convert millilitres to litres 27 00:01:28,228 --> 00:01:33,971 minutes will remain, but I need to remove kilograms. 28 00:01:34,098 --> 00:01:38,086 For some people, whether to divide or multiply by 1000 29 00:01:38,234 --> 00:01:40,942 and divide or multiply the the body mass becomes 30 00:01:41,078 --> 00:01:42,504 a little confusing. 31 00:01:42,601 --> 00:01:44,915 So setting up in this manner helps you decide 32 00:01:45,016 --> 00:01:46,862 whether you need to divide or multiply. 33 00:01:46,975 --> 00:01:49,561 Again the principle I am using, 34 00:01:49,657 --> 00:01:56,333 is that if one unit is on the numerator, for this example 'ml' 35 00:01:56,487 --> 00:02:04,689 I can multiply by a conversion factor and put the 'ml' on the denominator in the conversion factor, 36 00:02:04,822 --> 00:02:06,197 and those two will cancel out. 37 00:02:06,362 --> 00:02:09,521 We know how how many millilitres are in 1 litre. 38 00:02:09,682 --> 00:02:11,429 That is what we are trying to convert to here. 39 00:02:11,551 --> 00:02:15,303 There is 1000 ml in 1 L. 40 00:02:15,465 --> 00:02:20,969 If I stopped at this point, by cancelling out 'ml' 41 00:02:21,155 --> 00:02:24,953 I would take 45 and divide by 1000. 42 00:02:25,140 --> 00:02:27,487 However, if I stopped at this point, 43 00:02:27,648 --> 00:02:30,689 I would end up with litres per kilogram per minute 44 00:02:30,817 --> 00:02:35,986 Remember an absolute value is measured in L/min. 45 00:02:36,113 --> 00:02:41,397 Therefore, I must also "get rid" of the kilograms. 46 00:02:41,493 --> 00:02:45,432 So I need to either divide or multiply by kg. 47 00:02:45,577 --> 00:02:47,187 For some people, what to do may be clear to you. 48 00:02:47,264 --> 00:02:48,286 For others, not so much. 49 00:02:48,286 --> 00:02:50,250 We are going to use the same principle again. 50 00:02:50,412 --> 00:02:54,000 We need to "remove" kg in the next conversion factor. 51 00:02:54,125 --> 00:02:57,321 And it is on the denominator, on the left hand side. 52 00:02:57,471 --> 00:03:01,964 In order to cancel it out, I need to put is on the numerator. 53 00:03:02,090 --> 00:03:04,343 Remember top is going to cancel out bottom. 54 00:03:04,445 --> 00:03:09,890 Let's say for this example, the person is 78 kg. 55 00:03:10,044 --> 00:03:11,730 And again that is over '1'. 56 00:03:11,951 --> 00:03:14,090 'kg' will cancel each other out. 57 00:03:14,253 --> 00:03:16,246 Top cancels out bottom. 58 00:03:16,408 --> 00:03:20,539 To finish this off, all I need to do, is multiply all 59 00:03:20,669 --> 00:03:23,918 numbers together and divide by all the bottom numbers. 60 00:03:23,938 --> 00:03:28,083 Because anything divided or multiplied by one 61 00:03:28,280 --> 00:03:31,207 is one, I am going to worry about the numbers 62 00:03:31,313 --> 00:03:32,928 that are not one. 63 00:03:33,179 --> 00:03:36,252 I am going to take 45 and multiply it by 78 64 00:03:36,438 --> 00:03:38,292 and divide by 1000. 65 00:03:38,448 --> 00:03:44,803 This gives me the answer of 3.51 litres per 1 min. 66 00:03:45,020 --> 00:03:50,347 In this example, I have converted a relative VO2max 67 00:03:50,536 --> 00:03:54,500 of 45 ml per kg per minute and converted it 68 00:03:54,636 --> 00:03:59,249 to an absolute value of 3.51 litres per minute. 69 00:04:01,108 --> 00:04:04,471 Let's do another example now. 70 00:04:04,719 --> 00:04:11,869 I want you to convert Stanley's relative VO2 of 30 ml per kg per minute 71 00:04:11,995 --> 00:04:16,335 to an absolute VO2 value in L/min. 72 00:04:16,498 --> 00:04:19,375 His body mass is 80 kg. 73 00:04:19,499 --> 00:04:23,801 Please pause this video now. Try this out on your own. 74 00:04:23,896 --> 00:04:28,026 Once you have come up with the answer, or if you get stuck, press play again. 75 00:04:34,098 --> 00:04:40,011 Again we are converting a relative value in ml per kg per min. 76 00:04:40,081 --> 00:04:44,095 to an absolute value, in L/min. 77 00:04:44,282 --> 00:04:50,511 Stanley's relative value is 30 ml per 1 kg minute 78 00:04:50,669 --> 00:04:56,394 We want to convert ml to L. 79 00:04:56,530 --> 00:05:01,715 We set it up so that the numerator cancels out the denominator. 80 00:05:01,850 --> 00:05:06,511 We know there is 1000 ml per 1 L. 81 00:05:06,700 --> 00:05:10,023 'ml' cancel out. 82 00:05:10,181 --> 00:05:15,692 We need to multiply by kg because 83 00:05:15,819 --> 00:05:18,729 in the relative value it is on the denominator. 84 00:05:18,866 --> 00:05:20,671 We need to kg on the numerator. 85 00:05:20,799 --> 00:05:24,504 And we know Stanley is 80 kg. 86 00:05:24,634 --> 00:05:28,289 'kg' cancel out. 87 00:05:28,456 --> 00:05:31,844 In this example, I am going to take 88 00:05:32,032 --> 00:05:35,697 30 multiplied by 80 and divide by 1000 89 00:05:35,861 --> 00:05:41,124 to get my absolute value of 2.4 L/min.