Mountain Bike and Time Trial Training

BY IN Exercise Institute News On May 22, 2015

Effort is a difficult concept to try and quantify. Both Heart rate and Power can assist in quantifying effort, but they are measuring different aspects of human functioning and output. In this article we review how both quantities can be used to infer effort and how power can be best used to replicate the specific demands an athlete might experience across different cycling conditions such as Time Trial and Mountain Bike (MTB) racing.

Mountain Bike Riding

Below we have the instance of a Mountain Bike race. Notable are the short bursts of power (the pink line) as the cyclist applies large amounts of effort, then recovers as they navigate technical sections, then repeating this cycle onwards across different sections of terrain. The average power for this section was around 280 watts, the normalized power was 330 watts, meaning the range with which power was produced was quite vast (either high outputs or no outputs). Note that power output and the heart rate output (red line) do not tend to reflect, or parallel the other.

data mtb

Mountain Bike Power Data

Time Trial Riding

In the next image below we have a power trace from a time trial event, here the power output is very consistent and steady with average power and normalized power basically equal, meaning the variation in outputs to elicit a 304 watt average was minimal. Note the consistency in output here, the power line largely parallels the heart rate line.

data TT

Time Trial Power Data

Considering the MTB profile and time trial profile averaged power outputs similar to the athlete’s maximal sustainable output (threshold power) you could argue that the effort applied on both instances was maximal. However this observation is limited in that it does not account for the variance in outputs require to complete either task. Why is this important?

How to Train for Either

How an individual trains for each event is critical to maximizing your gains. Importantly using Heart rate as a guide may be misleading as it tends to smooth over critical events unique to the type of riding being completed. For example the heart rate trace during the MTB event was not as variable as the power output, meaning this analysis alone would not qualify the demands of a MTB event. Alternatively the Time Trial event saw both the heart rate and power data parallel the other. This then leads us to ask the question, “how best can you train for either discipline?”

For time trial efforts some training needs to be replicated at constant steady state outputs, where the muscle contractions are constant in force application and consistency IN THE SADDLE. Alternatively for MTB riding repeated maximal bouts of effort are required to replicate the demands of an event were opportunity to apply effort is segmented and occur for short periods inter-spaced by enforced rest. Such as climbing a hill hard to get up a steep incline then descending a tight descent with loose gravel, this would result in segmented power output. Much of this effort may occur in and out of the saddle.

Taken together, the power data allows us to look into the demands of each event specifically. Here the athlete can replicate the demands of their event by following training that allows for a similar power response: in MTB riding short bursts of high power, with short periods of recovery reflect the event demands; or in the case of Time Trial riding longer steady state efforts at threshold output are indicated. Using a HR monitor or a power meter in training will enable you to qualify how your training is replicating the demands of your event, however you can also use a structured training plan to ensure that irrespective of your ability to read power numbers or Heart rate trace, you are replicating the demands of your event.

Training programs should be tailored to meet some of the demand specific to these unique events. Simply training hard may not be enough if you really want to fast track your adaption rate!

Hall Cycling supplies and installs Verve: Infocrank power meters

-Written by Brad Hall, Brad has a degree in Exercise Science and Psychology (Hons.) AMAPS


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