Edited by Robert Edmonds The full edition with pictures can be viewed by clicking on the link above.
Allowing for time spent on orienteering course or in planning an optimum route on a rogaine takes into account many factors. An old rule of thumb for a fit orienteer was to allow 5 minutes per km, 5 minutes per 100 metres climb and 1 minute per control. A course of 12.4 km with 300 metres climb and 13 controls would be expected to take about 90 minutes. Of course, as you get slower and older you learn to make the necessary adjustments. The type of vegetation and terrain you will have to contend with will also affect your time. Naismith’s Rule is handy to use when planning a rogaining route. Once you know your expected speed and you have a rough idea of percentage climb you should be able to calculate the distance you might cover. Nightime adds another dimension. Distance covered is very dependent on the terrain and availability of tracks.
Naismith’s Rule is a rule of thumb that helps in the planning of a walking or hiking expedition by calculating how long it will take to walk the route, including ascents. The rule was devised by William W. Naismith, a Scottish mountaineer, in 1892. The basic rule is as follows:
Allow 1 hour for every 5 km, plus 1 hour for every 600 metres of ascent. The basic rule assumes hikers of reasonable fitness, on typical terrain, under normal conditions. It does not account for delays, such as extended breaks for rest or sight-seeing, or for navigational obstacles. For planning expeditions or walks a party leader may use the rule in putting together the trip plan.
Alternatively, the rule can be used to determine the equivalent flat distance of a route. This is achieved by recognising that Naismith’s Rule implies equivalence between distance and climb in time terms: For convenience an 8 to 1 rule can be used. So, for example, a route of 20 km with 1600 metres of climb has an equivalent flat distance of 20 + 1.6 × 8 = 32.8 km. Assuming an individual can maintain a speed on the flat of 5 km/h (walking pace), the route will take 6 hours and 34 minutes. The simplicity of this approach is that the time taken can be easily adjusted for an individual’s own (chosen) speed on the flat; at 8 km/h (flat speed) the route will take 4 hours and 6 minutes. The rule has been tested on fell running times and found to be reliable.
In practice, the results of Naismith’s Rule are usually considered the minimum time necessary to complete a route. Over the years several “corrections” have been formulated in an attempt to make the rule more accurate. The most common correction is to add 25% or 50% to the time found with Naismith’s Rule. While this may be more accurate for some people or under certain conditions, it does not explicitly account for any additional variables. The accuracy of some corrections is disputed by some, in particular the speed at which walkers descend a gentle slope.
Tranter’s corrections make adjustments for fitness and fatigue. Fitness is determined by the time it takes to climb 300 m over a distance of 800 m. Additional adjustments for poor terrain or conditions can be estimated by dropping one or more fitness levels.
For example, if Naismith’s Rule estimates a journey time of 9 hours and your fitness level is 25, you should allow 11.5 hours.
Other common corrections are: see full article