To figure out how to feed and hydrate in a mountain long endurance race which the ” Magredi Mountain Trail 100 Mile “, we must know the location and energy consumption of the race, the latter aspect does not simply regard the running trail.


Would start therefore from the energy consumption of the race than on the treadmill flat is 0.97 kcal / kg / km: the peculiarity that stands out from this data is that consumption of the race is speed-independent, characteristic that distinguishes them from energy consumption by the gear, in which consumption is proportional to the speed, going from 0.30 kcal / kg / km for the slow path (4km / h) up to 0.72 kcal / kg / km for the fast path (in 6km / h).

Simplifying things we can consider the average energy cost of MMT100 equal to 1kcal / kg / km : the approximation is acceptable in my view since on the one hand, there are many variables that on one hand the increase and on the other the decrease.

This reduces the energy cost of the race:

  • some traits that inevitably be walked : the stroke energy cost is much lower than that of the stroke (although the greater the slope, the more it is close to that of the race, v. over)
  • about a third of the race includes running in descent , when the consumption decreases significantly

This increases the cost of travel in mountain ultratrail:

  • the camelbak : less coordinated as it makes the gesture of the race
  • the mileage : 40 km after the gesture of the race becomes less fluid and less economical. It is estimated that after this distance the 0.12% increases the cost for each kilometer traveled.
  • the bottom : the path and the dirt roads are not a treadmill and their irregularity results in increased energy requirements


An analysis of the energy cost of walking and running at various inclines, both positive and negative has been realized in a work of 2002 ( Energy cost of walking and running at extreme uphill and downhill brooms , J App Physiol 93: 1039-1046, 2002), from which one can derive the consumption data (measured on treadmill and 10 athletes).

For the journey fuel consumption at different slopes are given below:

  • for slope – 45% of the way the consumption is 0.83 kcal / kg / km (x 2.2 times the baseline)
  • for slope – 40% of the way the consumption is 0.77 kcal / kg / km (x 2.0 times the baseline)
  • for slope – 35% of the way the consumption is 0.64 kcal / kg / km (x 1.6 times the baseline)
  • for slope – 30% of the way the consumption is 0.52 kcal / kg / km (x 1.3 times the baseline)
  • for slope – 20% of the way the consumption is 0.31 kcal / kg / km (x 0.8 times the baseline)
  • for slope – 10% of the way the consumption is 0.19 kcal / kg / km (x 0.5 times the baseline)
  • level consumption of the journey is 0.39 kcal / kg / km
  • for slope of + 10% on the way consumption is 1.12 kcal / kg / km (x 2.9 times the baseline)
  • for slope of + 20% on the way consumption is 1.93 kcal / kg / km (x 4.9 times the baseline)
  • for slope of + 30% on the way consumption is 2.70 kcal / kg / km (x 6.9 times the baseline)
  • for slope of + 35% on the way consumption is 3.04 kcal / kg / km (x 7.8 times the baseline)
  • for slope of + 40% on the way consumption is 3.52 kcal / kg / km (x 9.0 times the baseline)
  • for slope of + 45% on the way consumption is 4.12 kcal / kg / km (x 10.6 times the baseline)

The data are shown in the graph 1, in which the blue columns express the consumption expressed in kcal / kg / km: it is apparent from the fact that the lower consumption is had for negative slopes between 10-15% less. For lower slopes consumption increases as it is necessary to use energy “braking”. The energy expenditure, however, is much greater for the high gradients. One figure is very interesting the fact that for the path to gradients already 10% consumption (1.1 kcal / kg / km), is considerably higher (+ 38%) to that of the race in the floor (0.8 kcal / kg / km) : So for those who want to consume calories run- -not being able to walk, it is recommended that you’re driving downhill, by virtue of the substantial increased energy expenditure.


CHART 1 : energy cost (kcal / kg / km) march to different slopes



The expenditure can also be viewed not in absolute value but relative (graph 2), taking as reference the path of the energy consumption in the plane and considering it equal to one. In this way from the chart 2 we can better quantify the increase due to the slope that if doubles in extreme descents (-45%), for extreme climbs (+ 45%) reaches values ​​almost 11 times higher than those of the journey flat.


GRAPH 2 : relative energy cost (compared to stroll to, regarded as a numerical value of 1) of the march to different slopes


For the race consumption to different slopes are given below:

  • for slope – 45% consumption of the race is 0.94 kcal / kg / km (x 1.2 times the baseline)
  • for slope – 40% consumption of the race is 0.83 kcal / kg / km (x 1.0 times the baseline)
  • for slope – 35% consumption of the race is 0.67 kcal / kg / km (x 0.8 times the baseline)
  • for slope – 30% consumption of the race is 0.58 kcal / kg / km (x 0.7 times the baseline)
  • for slope – 20% consumption of the race is 0.41 kcal / kg / km (x 0.5 times the baseline)
  • for slope – 10% consumption of the race is 0.46 kcal / kg / km (x 0.6 times the baseline)
  • flat consumption of racing is 0.81 kcal / kg / km
  • for slope of + 10% consumption of the race is 1.37 kcal / kg / km (x 1.7 times the baseline)
  • for slope of + 20% consumption of the race is 2.13 kcal / kg / km (x 2.6 times the baseline)
  • for slope of + 30% consumption of the race is 2.99 kcal / kg / km (x 3.7 times the baseline)
  • for slope of + 35% consumption of the race is 3.45 kcal / kg / km (x 4.3 times the baseline)
  • for slope of + 40% consumption of the race is 4.02 kcal / kg / km (x 5.0 times the baseline)
  • for slope of + 45% consumption of the race is 4.52 kcal / kg / km (x 5.6 times the baseline)

The run data are presented in chart 3, in which the green columns express the consumption (expressed in kcal / kg / km): in contrast to what happens to the path (when the minor consumption applies for negative slopes of between minus 10 -15%), for running the less energy you have for more negative slopes, ie between 15-20% less. Also for the race, for still lower pitches, consumption tends to increase and is due to the energy required for braking the inertia of the body downhill. Also for the race, increasing the energy expenditure of the slope gradually becomes much more high (and -this beyond mechanical factors or related all’allenamento- is one of the reasons why the body prefers to walk than run). At higher gradients (over 20%) the stroke of the energy cost is almost equivalent to that of the path: resulting of only 9-12% lower.


GRAPH 3 : energy cost (kcal / kg / km) race at different slopes


The analysis of the relative data (graph 4), which consider equal to 1 the consumption of travel in plan, express an interesting glance on the race: it increases by 5.5 times for the extreme slopes , when it probably reaches both the maximum power consumption of the “machine-man.”


GRAPH 4 : Relative energy cost (compared to running on the flat, regarded as a numerical value of 1) of different slopes to race


5 The following graph represents the difference of energy consumption (expressed in kcal / kg / km) between path (blue) and stroke (green) at different slopes: note that the most significant differences are found for slopes between the top and the less than 10%, for instead blunted in most high positive or negative slopes.


GRAPH 5 : Comparison of energy cost (kcal / kg / km) between gear and race to different slopes


The final analysis is the comparison of the relative changes of consumption in relation to the journey and ride plan, the expenditure of which the value of 1 is assigned.


FIGURE 6 : comparison of relative energy cost (compared to running and to walk on level ground, considered as a numerical value of 1) on different slopes


The figure that stands out is that an increase of the slope both the two modes become much more expensive but grows much more the consumption (relative) of the path (almost 11 times) compared to that of the stroke (5.6 times).


The characteristics that differentiate and complicate the calculation of energy consumption compared to running on the flat are the presence of ups and downs: extrapolate from energy costs obtained on treadmill at different slopes is a complex operation to be done and little predictive the exact value, for the presence of many variables. I find it more useful to refer back to the hypothesis of metabolic approximation that 100 meters of climb equate 1km running flat: Even having personally tested this equivalence, it seems to me that the estimate it provides is reasonably close to the actual real consumption.

According to this hypothesis the 7200 meters of elevation gain therefore equals 72,0km, which is going to add up to 160,5km route, achieving an equivalent distance of 232.5 kilometers, which differentiate them from the linear call -km effort.


Postulate that the value of 1kcal / kg / km is a good starting point to calculate the total energy cost of a similar race (also seen that by virtue of the length of the race, do not care get a scientific accuracy), we try to make a useful estimate in order to get an indication practice to figure out how many calories are needed to complete the race effort and therefore it is important to try to integrate.

If we consider a person of 70kg which hypothetically wear a 5 kg equipment (shoes, sticks, camelback, clothing, etc.), so a total of 75kg (remember that consumption is not reported to the bare weight, but the total weight), its consumption on the race will be 1 / kcal / kg / km x 75kg x 232,5km = 17437 kcal . Given the length of the duration of the race, this figure we must also add the consumption of basal metabolic rate that is equal to 1kcal / kg / h: if we assume that our athlete ends the race in 36 hours , we should multiply its weight (70kg : in this case I do not consider the equipment) for the number of hours (36), obtaining an addition 2520 kcal . The race will therefore cost 17 ​​437 kcal (energy movement) + 2520 kcal (energy of basal metabolism), ie 19 957 kcal (approximated at 20,000 kcal ).


At this point everyone according to their weight and what they hypothesized for the equipment, it can realize the multiplication with its data and obtain an estimate of their personal energy consumption. Remember that the formula is as follows: weight (body + specification) x 235.5 ( kmsf ) + weight (body) x hours planned race = n ° kilocalories.


With how much energy available leave for the MMT100? Sugars (collected in the form of glycogen in the muscles and liver) are about 500g, for a total of 2000kcal : are the primary and most valuable source of energy for the sport, as they allow you to go and go definitely stronger than the other fuel, ie the fat, an almost inexhaustible supply in our bodies, but lower power.

If our athlete of 75kg (including equipment) maybe-imagining to be at a maratonina- departed rocket and proceeded at full throttle (= all sugar), consuming 75 kcal per km it would be able to travel about 27 km (2000 kcal / 75kg), planting already on the climb that leads to Montereale Piancavallo!

Given that in the long-distance races it is impossible to consume 100% of sugars, consider the two extreme cases, in which in the first case our athlete corrected by a side at a pace suited to its capacity and not reintegrate other than water, in the latter case would introduce a regular sugar.


Doing the math, we can understand that having a 2,000 kcal tank having an energy expenditure of 20,000 kcal, means that to get to the end our athlete should use a mixture in which the 10% energy deriving by the sugars and 90% by the reserve for which fat is almost unlimited, but for which combustion is always necessary that there is a minimum amount of sugars ( ” fat burn in the fire of sugars “): with such a low portion of sugars the race is impossible, and even with a simple walk would be very difficult to come to the finish line.


The opposite is represented by a scrupulous athlete who assume every hour one liter of beverage containing 8% of simple sugars: 36 liters in 36 hours is not an easy goal to achieve, but ideally possible.

L ‘ 8% of sugar means that each in each liter of water were dissolved 80 grams of sugar (typical dose of a normal integrator = 320 kcal / liter ): with these quantities could in from a side idratarci adequately without risking the iponatriamia ( that would very likely if it took only water, without added mineral salts), on the other hand we could add a substantial amount of energy in the form of simple sugars, which are the most useful from the point of view of energy since the faster and much more assimilable performance than the energy obtainable from fat (premium gasoline, diesel instead …). The 80 grams moltiplicatii for 36 liters correspond in fact to 2880 grams of sugar ie to 11520 kcal . Adding to this amount of (energy introduced that of the reserve of muscle and liver glycogen 2000 kcal ) I get a quantity of sugar available 13520 kcal , which compared with the demand from the consuming of the race (20,000 kcal), would mean the 68% of energy of sugar origin and 32% of fatty origin.

A far cry from the opposite case and an amount of energy that sugar potentially allows me to get to the finish running.


I considered the two opposites in which the one hand there is no caloric integration, the other an ideal complement caloric: in the middle there is the compromise that each strategy will succeed or will choose to implement , recalling that the optimum hydration capacity can be improved and should be coached. It should be taken into account that the maximum water absorption capacity is 2L per hour , but that in the course of a race is difficult to achieve a hydration capacity of 1L to now : this ability can be trained and in general it is reasonable to obtain a ‘hydration equal to 0,8L / hr .

The reality of what we do is in the middle, taking into account that definitely a good supply strategy is useful and necessary to arrive at the finish line and in good condition.

Dropping the speech specifically MMT100miles the race, my advice is to start with 2 bottles of 750ml (1.5 liters), which multiplied by 16 refreshments equivalent to 24 liters (=7680 kcal ). Added to the starting calories (2000kcal) it means to have 9680 kcal , about 20,000 kcal needed: decent pace, guaranteed by a mixture with 48% sugar and52% fat.


Apart from the two flasks departure preloaded, it remains to prepare the following 2 for each of the next 15 Refreshments: I suggest you prepare the right integrator portion calculated for 1.5 liters and place on 15 bags (like those from the freezer), so that the pauses of each refreshment the athlete stops, fills the water bottles of supplement and water (you can choose if you want to distribute it in a half or the other half, or all the integrator in a more concentrated and nell’altre water, or something in between). It is true that one can argue that this means starting with weight 1kg more, but I think the price is worth the candle (bring along the race will cost us a hundred kcal, but there will provide nearly 100 times as many), since the weight will decline gradually as the athlete will be more tired. Also other is the absorption of a liquid in small sips between the refreshment, else what is assimilated later all’ingurgitare a large amount during the short break of dining: if when the athlete stops at the refreshment then able to drink a ‘additional interest will be other liquid calories you earn. Finally, from my personal experience I never found refreshment in which the supplement was diluted in the correct proportion.


Not everyone is able to absorb high amounts of liquids and for many the pangs of hunger can be unstoppable, so it will be more or less inevitable temptation to solid foods, which can and must be taken for the welfare global athlete but whose caloric intake will hardly be able to be higher than that suggested by the optimal integration. Some may say that the sandwich with salami, chocolate, beer gives more energy sugared water: this is partly true because although the caloric value of these or similar foods may be higher, their slow and complex digestion absorb energy that would subtracted that necessary to muscles.

As for solid foods, I would say that the fruit has a rapid absorption and is preferred, but you have to be careful because it can stimulate peristalsis thereby cause annoying bowel movements: banana and dried fruits can be best placed to do so.

What definitely would not recommend are the sausages , the cheeses , the eggs and alcohol .

Preferred rather complex sugars type bread and jam , better than all other types of cookies. A complex sugar, but quite easily absorbable is that of potato boiled. You do not overestimate the chocolate , useful for the mind, but slowly absorbed by the high amount of fat. Another very overrated as a supplement drink is Coca Cola (it will be because of all those bubbles …): Not enough is his contribution in salts and hypertonic (= ie with a high sugar content: 10%) too high compared with the optimal ( 6-8%). Even the it is difficult to assess: a few minerals, highly variable content of sugars that are often dissolved “nose” (though those are hypertonic prepackaged liquids).

An interesting food liquid but which also contains a proportion of protein and fat is the broth , in which there are also valuable minerals and vitamins.

Dott. FRANCESCUTTO Ciro Antonio

Sport Physician