Triathlon´s Vital Signs

We tend to forget what vital signs mean.  In Medicine, vital signs are the most important aspect of the patient to consider.  I follow a 95-year-old patient daily and the vital signs are our guidelines for treatment.  Historically we have four vital signs: blood pressure, temperature, heart rate and respiratory rate.  The vital signs should change as much as they could change in teenager for a 95-year old lady.  When she runs out of oxygen in the middle of the night because she removes it while sleeping, her pulse can be 10 beats higher in the morning as if she had a hard work out during the night.  Her saturation can drop to low 80’s if she does not have oxygen at night.  I do not need to know what happened during the night when checking the heart rate in the morning; during the day her saturation stays above 92 without oxygen.

Temperature should not change or being above 37 degrees Celsius.  If it is higher than that we should stop practice for the day at least and a differential diagnosis for fever should take place.  DO NOT LET THE DIAGNOSIS OF HAVING AN INFECTION FOOL YOU.  Above 37 degrees Celsius of core temperature can help you to understand athlete´s life; is the athlete resting well? Is the athlete eating well? Check the Complete Blood Count and find out about the erythrocyte production.  Even if the athlete does not have anemia, nutrition could be a problem for repetitive infections (we all have bugs but other factors play a role in athlete’s illness).  Even if athletes eat well, resting is another variable; and by the same token, lesions in athletes (ask the footballers).  We found out that our triathletes were out in the middle of night after we checked lactate levels at rest in the morning and they were 2 or above.

High blood pressure should not be present in athletes unless something very important is happening somatically.  Is the athlete withdrawing from drugs? Is the athletes falling into kidney failure (you should have many other signs by then)?  No athlete should faint unless something is really bad (Laurent Vidal fainted years before he died).

Respiratory rate and heart rate are intertwined.  The second to second regulation is done by the amount of CO2 in arterial blood.  They both go up when CO2 increases but there are adaptations to this phenomenon of CO2 increment.  The respiratory rate adapts first, so the heart rate stayed up and helps to monitor fitness or CO2 retention without the need of getting Arterial Blood Gasses in somebody who is monitored several times during the day.  This is our observation in a 95-year–old lady who has been monitored for more than a year.

Weight is not a vital sign but helps to monitor patients.  Weight increment of 1.5 kilograms is the norm comparing the morning weight and evening weight in the same athlete.

How can we apply this to triathlon? Let’s take the heart rate and weight.  We have had the cardiac monitor for several decades already.  It is part of an educated triathlete, but how much we want to ignore about weight?

There is a study (many studies have been published) which gives information about weight in horses the way we can understand running in humans:

Table 2 shows the velocity versus oxygen consumption for a TB horse.  Column one is the horse speed (feet per second, ft/sec) on the treadmill, column two through five are the oxygen consumption values (ml/kg/min) on the treadmill, column three for running on sand (simulate the race track), column four is for a jockey weight of 130 pounds and the last column for a jockey of 110 pounds.  The table shows that at a constant speed the oxygen required increases as the load condition increases running in sand or carrying weight.

Table 2:

Velocity                Oxygen                 Running          Jockey           Jockey

                         Consumption in Sand           Weight           Weight

Vel, ft/sec	O2, ml/kg/min	1.2	130	110
5	15.5	18.6	20.84	20.49
10	26	31.2	34.96	34.38
15	36.5	43.8	49.07	48.26
20	47	56.4	63.19	62.14
25	57.5	69	77.31	76.03
30	68	81.6	91.42	89.91
35	78.5	94.2	105.54	103.79
40	89	106.8	119.66	117.68
45	99.5	119.4	133.77	131.56
50	110	132	147.89	145.44
55	120.5	144.6	162.01	159.33
60	131	157.2	176.12	173.21
65	141.5	169.8	190.24	187.09
70	152	182.4	204.36	200.98
75	162.5	195	218.47	214.86
80	173	207.6	232.59	228.74
85	183.5	220.2	246.71	242.63

The same thing is happening to humans running but the effort can be greater when relating them to the center of gravity and weight.

The effect of weight at other locations other than the center of gravity can have a significant impact on oxygen consumption levels.  Myers (1985) found that the cost of adding a given mass to the limbs is significantly greater than adding it to the center of mass and that this effect becomes more pronounced as the limb loads are moved distally (towards the foot).  Miller (1987) showed a 0.8% increase in oxygen consumption for ankle weights of 100 grams on human runners.  A 600-gram weight at the center of gravity would result in the same increase of oxygen consumption.  Relative to horse racing, any increase in extra weight carried along the leg and at the hoof could impact on a horse’s performance.  For example on a muddy or sloppy day a large horse (large hoof) could end up carrying extra dirt in its hoof relative to a smaller horse (smaller hoof).  Also the come from behind type of runner could have additional weight along the legs from mud being thrown back from horse’s in front.  This extra weight could be enough to cost a win.

We are not kicking a dead horse!  Flying while running has implications for performance if we consider weight into the equation.  If we have a cadence of 200 rpm running a mile in 4 minutes and we cannot compete in triathlon running the last 10k, it is because we cannot fly in triathlon after the effort on the bike or due to the way we pedal during the race.  In addition to what we know scientifically we have many examples of low cadence running and inability to run in an Olympic distance triathlon. I have seen Lukas Verzbicas running the last 10k in Puerto Progreso this last weekend and he was running above 33 minutes the 10k.  I have seen videos of Alan Webb running after swimming and biking and he was not able to “fly.” They keep the same cadence without flying.  What have we learned from horses?  Keeping the weight (if extra-weight) at the center of gravity does not affect performance so much.  Increasing cadence is another one, it keeps the center of gravity in front of us most of the time; horses increase cadence to go faster because they cannot increase flying time as humans do.  Flying after the bike is very difficult to do and sometimes impossible because the way we develop our muscle doing our bicycling training.

How we can keep weight at the center of gravity? We need technique for running.  Yes, there is a technique for running and we have pointed out in this blog.

28 juin 2013

Triathlon and Running Technique