Limitations to Walking Performance

by Patti Finke M.S., Team Oregon
What are the limitations to walking performance, what governs how fast you can walk or how far you can go? As more and more walkers compete in organized events, they view themselves as athletes and begin to look for information to improve performance, either walking a specific event in a faster time or choosing events of longer distances. As a coach, an exercise physiologist, a runner, cyclist and a competitor in a number of walking events, I have been looking for the answers to these questions for a number of years.

Exercise physiologists have long known and have well documented VO2 Max as the quantifier of the body's work capacity. This capacity is maximal oxygen uptake or your capacity for aerobic energy transfer or aerobic "horsepower". An improvement in this capacity increases the amount of work you can do or means that you can walk faster or further. The variables that influence VO2 Max are heredity, state of training, age sex and body composition. Heredity is most important influence making picking faster parents the best way to be faster . Even though heredity determines where you start, training can increase performance by changes of 20 -25% with some changes of 50% reported. How can you find out what your potential is, how do they test for VO2 Max and/ or is it important to know? Treadmill tests in an exercise physiology lab are fairly complex and expensive, but can be extremely accurate. Submaximal or maximal treadmill tests in the doctors office or fitness facility use heart rate to predict VO2 Max within 10-20% of the actual value. The Rockport Walking Test can be used by walkers to estimate VO2 Max, but may underestimate because of the motor skills involved in walking. You can use the Rockport Test, not as the actual measure of your VO2 Max, but as a way to measure progress or assess intensity levels as described below.

Beginning walkers may be limited by cardiovascular fitness and can use heart rate to keep from working too hard while walking. As walkers become more fit and use other fitness activities, using heart rate as a training and/or racing guide becomes much more complex. For runners and other athletes, heart rate has been studied, documented and well defined. We have been coaching runners using heart rate and heart rate monitors for over three years with great success and would like to establish the same kinds of guidelines for walkers.

Fast walking is a motor skill that requires a great deal of practice. As I have tested several hundred walkers using the Rockport test , I have seen that technique, not exertional level as monitored by heart rate is the limiting factor. Fast walking is a SKILL sport. We have seen big changes of 1- 5 minutes a mile in walkers who have taken our walking technique classes and who have practiced technique using speedwork and racing. If you would like to get faster, it is appropriate to take some walking technique classes..

The major limiting factor for distance is the availability and utilization of fuel. The factors that determine the fuel choice and usage are the intensity and duration of the exercise. You can influence the percentages and extend the limits by training specifically and competing (walking) at the correct intensity. Heart rate and a heart rate monitor can be extremely useful in the specific training and to gauge the intensity at which to compete. As the distance of the event gets longer the intensity at which you can work gets lower. We have compiled a table of heart rates which represent a 5% decrease in effort for each column to the right. I have assumed that walkers actually complete a Rockport test at about a 90% functional effort because of the motor skill involved, probably compete at the 90% effort and should be training at the 80% effort. Take your Rockport HR and use the column below to estimate the effort for a race of the distances shown. To train use the column 2 to the right.

Rockport  HR  161   155  149  143  138  133  129  124  120  116
5K            157   151  146  140  135  131  126  122  118  114
10K           152   146  141  136  131  126  122  118  114  110
20 Miles      143   138  133  128  124  119  115  112  108  105
Marathon      141   136  131  126  122  118  114  110  107  103
An example of the usefulness of the table may be in walking a marathon. While we all have enough stored fuel (fat) to walk the marathon or even longer distances, fat can only be burned as a fuel if we have some glycogen (sugar) stores left either in the muscles or the liver. If we start the marathon too fast ( a common marathon mistake) using up the available glycogen, somewhere after 20 miles the dreaded "wall" may become a factor. A pulse rate monitor and the table could insure marathon success if, of course, you have done the proper training to maximize the fat burning.

The Rockport Walking test is a maximal effort walked for 1 mile with time and Heart Rate recorded immediately upon completion. It can be done on any measured mile, but is probably easiest done at the track, You should warm up at least 2 laps, the walk 4 laps all out, record your time and take your pulse, then cool down for 2 laps.

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