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USING A HEART RATE MONITOR
Nigel Davies
The aim of this article is to assist the orienteer in achieving maximum athletic performance from available training time. The reader is assumed to be in good health and familiar with basic training principles such as warm up, stretching and cool down. Part Two in a series. Also see “Measuring performance with a heart rate monitor”, June 2004.
THE goal of every competitive orienteer is to optimise training so that maximum athletic performance potential is achieved. This is difficult enough for the full-time athlete with unlimited training time and a professional coach and harder still for the amateur, who has to fit limited training time around family and work responsibilities. OK – you are in your running gear, the weather is clement and you have an hour in which to train. Where are you going to run? How far and how fast will you run? Will you run at a constant pace or vary your pace? Will you run hills or flat and fast? Somewhere in this infinite range of possibilities is the right combination of training sessions for your athletic goals, but which is it, and what guidelines can we use to identify it? There are two common errors in planning training, either of which can prevent athletes from reaching their potential: 1. Training is performed at the wrong intensity. We either train with insufficient intensity to improve performance or we train with too much intensity and become sick, and;
2. We do the same type of training
every session and fail to develop one or more of the essential physical qualities required for orienteering – endurance, speed, hill climbing ability and so on. This article describes how a heart rate monitor can be used to assist in training at the optimum intensity and with the right mix of sessions.
Training at optimum intensity
Periodicity
Periodicity describes the process of exercising at an appropriate intensity to stress the system a little beyond previous limits and then allowing sufficient recovery time for the body to adapt to the stress and achieve an improvement in performance. This process is repeated with gradual increases in intensity so that, over time, we are able to work harder for longer.
There are several guidelines for optimising training intensity by using periodicity (and it should be noted that these are only guidelines, and may not apply equally to every athlete): • Increases in total exertion from week to week should be in the 5% range (see below for a discussion of exertion). However if we increased exertion by 5% every week then by the 52nd week we would be completing eight times more work than in the first week – if we survived that long. To avoid overtraining, schedule an easy week every three weeks – three steps forwards and one step backwards. Your ability to assimilate substantial increases in exertion will also depend on current proximity to your personal limits. Someone starting from a low base may be able to achieve an increase in weekly exertion of 100% or more over one year while an increase of this magnitude may not be achievable by someone who is already training at a high level. • Schedule an easy day every week, an easy week every month and an easy month every year. As we age, the frequency of easy sessions should be increased as recovery becomes slower. At age 54 I find that performance seems to benefit more from two easy days a week and an easy week every second week. • The same type of high intensity training session should not be repeated on successive days. You have just broken the one hour mark for 1,000 metres of ascent up Mt Wellington – congratulations! Flushed with success, do you attempt to repeat the achievement on the following day? No, take a weak cup of tea with an aspirin and enjoy a rest day instead. • Don’t do too much training at a high intensity – heart rate should not exceed anaerobic threshold for more than 20% of total training time over an extended period. Build a training pyramid with a wide base of aerobic exercise at the beginning of the year and later in the year you will be able to complete longer and harder anaerobic sessions as you prepare for championship events.
The best way to track periodicity is to keep a training diary. The writer has done this for several years – for the last 12 months by using the Polar training diary software. A heart rate monitor is worn for each training session and the results downloaded to a computer.
The diary for a typical month is shown in Figure 1.
Figure 1: Training diary: Training diary software makes it easier to monitor the frequency of sessions. Different sports and types of training session are automatically colour coded and performance statistics maintained. In the right margin is a summary of each week, showing number of sessions, total training time and total distance. A histogram showing the proportion of training time spent in different heart rate ranges helps maintain the right balance of intensity.
Ideally we should not increase total exertion by more than 5% from week to week – but how do we measure this? We cannot use total training time as a measure for the following reasons: • Five minutes running at race pace is approximately six times more stressful than five minutes running at long slow distance pace. • Long slow distance runs that exceed two hours stress the system 50% more than similar runs of less than two hours. • Race pace runs longer than one hour stress the system 20% more than race pace runs of less than one hour. • Exercising for the same period of time at the same heart rate in different sports creates different amounts of stress. This is due to the varying muscle mass used by different sports and the extent to which the sport resists gravity (cross country skiing and rowing are more stressful than running which is more stressful than cycling and so on).
The Polar training diary software compensates for these issues by converting exercise at any intensity and in any sport to a single ‘exertion’ figure. This information can be graphed and used to plan training loads. A graph of weekly exertion over a twelve month period is shown in Figure 2.
Orienteering stresses several different energy pathways – each of these needs to be developed to an appropriate level: • We need endurance to be able to run for up to 90 minutes.
This is developed by long slow distance training with a one to two hour run each week at about 70% of maximum heart rate. • We need sustained speed to be able to run for extended periods at a high percentage of maximum heart rate. This is developed by running at anaerobic threshold pace (uncomfortable but sustainable) for up to 60 minutes and by
short recovery interval training at 90% of maximum effort
over distances of 300 – 1500 metres. • We need to maintain and raise maximum effort so that 90% of a higher maximum effort results in a faster sustainable running speed. This is achieved by training at VO2 max pace (decidedly uncomfortable and sustainable for no longer than 10 - 12 minutes) and by long recovery interval training at up to 100% of maximum effort. • We need to be able to run strongly up hills. This is achieved by running long and short hill intervals at either anaerobic
threshold or VO2 max pace.
Figure 2: Exertion: Training in the first half of the year (A) was not successful as weekly training loads were increased too rapidly. Some over-long runs (Mt Anne Circuit, Cathedral Mt Circuit) resulted in three periods of extended fatigue and enforced recovery. Training in the second half of the year (B) was more successful, with gradual increments in training loads leading up the Easter events. The only blemish in this period was in January (C) when six successive days of orienteering races in New Zealand were followed by running the Kepler Track (68km). Had the writer acknowledged the established precedent of resting on the seventh day, then perhaps two weeks of training would not have been lost to illness.
Figure 3: running distance per week v average heart rate per session: This graph displays total weekly running distance (the columns) and average heart rate for each running session (the line). The goal is to keep the average heart rate line spiking up at an appropriate frequency to maintain race performance. A, B and C mark periods when there were no high heart rate sessions for up to six weeks, causing a deterioration in race performance. Similar graphs are used to track the frequency and duration of other markers, such as long slow distance runs and hill runs.
The Polar training diary software can be used to produce a number of customisable graphs that help the athlete review training patterns. This is illustrated in simplified form in Figure 3.
Summary
This article describes how a heart rate monitor and training diary software can be used to balance the intensity and frequency of different types of training to help achieve optimum performance from available training time.
Nigel Davies lives in Launceston, Tasmania, where he is a member of Esk Valley Orienteering Club. When not running in the bush he runs an IT training and consulting company. He has represented Australia at orienteering and duathlon and the United Kingdom at gymnastics. His ambition is to beat Hugh Moore (ACT) in the M100 class at the Australian Championships of 2050.
