Exercise Benefits of Incline Training

Most people report that weight loss and increased cardiovascular fitness are their principle
goals when beginning an exercise program. Increased muscular fitness and appearance are
also high on the list of goals. For the working professional, the over-extended, or the
individual not wanting to spend hours and hours at the gym, the search for optimal exercise
training is of preeminent importance. This search begins with bioenergetics and, as you will
see, ends with incline training.In order to enhance cardiovascular fitness, the lungs, heart, blood vessels, muscle tissue,
mitochondria, and the oxidative energy system must be stressed. This stress, often measured
by heart rate, results in improved function by some or all of the physiological components
involved. Research has shown that exercise intensities at or above 75% of age-predicted
maximal heart rate are needed to stimulate significant improvements in aerobic fitness.
Generally, exercisers must speed up their movement pace in order to elicit such a large
increase in heart rate. This increase in speed may increase risk of injury and, as seen below,
actually decreases the amount of fat utilized during exercise.
The oxidative energy system is the only system capable of utilizing large amounts of fat for
energy. In order to function as the predominant source of energy, the oxidative system
requires that exercise be performed at a relatively slow pace. This is a result of the many
enzyme reactions needed to transform fat tissue into a usable form. While a person is
walking, the oxidative system is able to provide the majority of energy, resulting in fat being
utilized to fuel. As an individual begins to run, caloric expenditure increases due to greater
amounts of muscle tissue activated in order to propel the body at a faster speed; however, the
rate of movement requires a gradual shift from reliance on aerobic energy production to
greater and greater reliance on anaerobic energy production. Running at faster speeds results
in a larger number of calories being burned but those calories are predominantly from
carbohydrate stores rather than stored fat. In order to burn larger amounts of fat, the amount
of muscle tissue activated must be increased while maintaining a slower pace of movement.
Enter incline training! Examining Physiological Changes during Treadmill Exercise
Recent research conducted under the direction of Dr. Matthew Rhea, Director of Human
Movement at A.T. Still University, demonstrates the changes that occur when an individual
exercises at different speeds and inclines on the Incline Trainer. This research used exercise
science tools to measure changes in heart rate, oxygen consumption, caloric expenditure, and
muscle activation under different exercise conditions. Among a group of 30 year old adults,
walking at 3 mph with 12% incline resulted in the same heart rate at running at 6 mph on flat
surface. The slower speed can be beneficial to reduce risk of injury during treadmill exercise
while still obtaining the needed cardiovascular benefits.
EMG measures, which identify the amount of muscle tissue activation, demonstrated
important changes with the use of incline as well. At 0% incline, only about 20% of muscle
tissue was activated in the legs. As incline was increased, muscle activity in the calf,
hamstring, and gluteus increased. At inclines above 15%, muscle tissue activation in the legs
approached and exceeded 75% of maximal isometric contraction.
Perhaps the most significant finding of this research was the change in fat utilization at slow
speeds and high inclines. With increased muscle activation at higher speeds and inclines,
calorie expenditure increases. If only speed is used to increased energy demand, the body
must use more and more carbohydrates as fuel because fat utilization takes too long.
However, with the use of incline to increase demand while keeping the speed at 2-3 mph,
physiological measures and calculations such as oxygen consumption and respiratory
exchange ration demonstrated that fat utilization increases dramatically. It was hypothesized
that the slower speeds allowed the processes involved in fat utilization to keep up with the
energy demand. At 2 mph and 16% incline, over 6 calories per minute from fat were utilized.
This was compared to less than 2 calories per minute from fat used at 6 mph and 0% incline.
These data demonstrate the increased physiological demands while walking or running at an
incline and present several useful applications of incline training. Individuals seeking
increases in muscular fitness, cardiovascular fitness, and weight loss can effectively use
incline to enhance the effectiveness of treadmill training. The most apparent benefits in these
areas occur at inclines above 10%.


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