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Friday, December 9, 2022
Dr. Brown: The science of exercise and effective workouts

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the Infohealth series at the Niagara-on-the-Lake Public Library.  

Dr. William Brown

Special to The Lake Report

In the 1980s through to the early 2000s, Harvard, Tufts and Boston universities developed an exercise program designed for women whose ages ranged from their 20s to their 90s.

The investigators wanted to know whether a modest strength-training program using simple in-home devices, including a few free weights, could significantly increase the women’s strength and reduce the risk of fractures. Both goals were achieved, even for those in their 80s and 90s.

One of the principal investigators – Miriam Nelson – went on to write several popular books based on the findings of the study, of which my favourite was her first book, “Strong Women Stay Young.” Unfortunately, the investigators ignored the role the brain plays in exercise.

I learned to downhill ski in my late 20s and remember my shaky beginnings – first master the snowplow and shortly thereafter, stem turns.

What was obvious then, was how quickly most skiers learned within a few days to make their first tentative parallel turns, even if it took much longer to make those turns look and feel effortless under all conditions and different slopes.

Those visible and felt changes were all about the brain learning how to co-ordinate the activities of muscles throughout the trunk and limbs, to make what was at first a conscious, effortful challenge into something experienced skiers are barely aware of, except for the pleasure of swishing down slopes and carving turns that beginners marvel at.

Experimental studies of the brain in rhesus monkeys when they learned new motor tasks revealed what you might expect.

Brain activity related to learning a new task was at the outset poorly focused and co-ordinated and tended to involve large areas of the brain.

And persistent repetition of the same task was associated with increasingly better focused and co-ordinated neural activity within the neocortex as the brain learned to carry out the assigned job more efficiently and fine-tune it’s activity in response to feedback from cues within the brain, muscles and elsewhere.

In one study the relative contributions of the brain and muscles to learning a new motor task was assessed. The earliest changes were expressed in how the brain controlled the muscles involved in the task – not in the muscles. The latter changes took several weeks to develop.

The earliest increases in the force with which voluntary muscle contractions were carried out were the result of the brain making adjustments in how the muscles were activated by the brain, by changing the firing rates and activity patterns of motor nerve cells in the neocortex and spinal cord and recruiting synergistic muscles to the task.

These and other studies of voluntary motor tasks illustrate the primacy of the brain in any motor activity, whether running, biking, playing tennis, swimming or strength-training. The muscles are important, of course, and often change their metabolic and contractile properties in response to training – but those changes are secondary to the underlying activity patterns governed by the brain.

Three points about any exercise program are important.

First, choose programs that involve as many major muscle groups as possible, such as the trunk and limbs at the same time, because those programs provide the best training buck for time spent.

Second, find a time and whatever programs you adopt – and stick to both.

Third, if you intend to use exercise as a tool for improving your cardiopulmonary fitness, you need to periodically increase the intensity of the exercise to a level that safely but significantly, increases your heart rate.

Runners accomplish this by picking up their pace at intervals – so-called interval training. The same periodic increases in effort should be adopted with road or stationary bikes, elliptical trainers or for that matter, strength-training.

The importance of intensity is illustrated by the effectiveness of short, intense training sessions. One popular example of which is the seven-minute workout training program, which involves 12 separate exercises, each designed to train different muscle groups carried out for 20 seconds and followed by a 10-second rest period before moving on to the next exercise in the series.

These short, but intense, training programs work because each exercise is carried out at a high intensity – more than enough to get the heart and respiratory rates up in the aerobic range.

Finally, while cross-country skiing may exemplify the principle of engaging as many muscle groups with as little impact on joints as possible, it’s hardly a practical solution here in Niagara-on-the-Lake.

Excellent indoor equivalents include elliptical trainers and, to a lesser extent, treadmills and stationary bikes. But whatever you choose, you need to remember to pick up the pace at intervals if you want to achieve those heart-lung benefits.

Finally, sometimes it helps to enlist the advice of a fitness trainer, especially if you are not familiar with the pros and cons of different training devices and how to get the best out of each while avoiding injuries.

You might want to check out that book by Miriam Nelson and have a look at the seven-minute workout

Merry Christmas and best wishes for a very fit 2021.