ANAEROBIC EXERCISE - RESISTANCE TRAINING

2. ANAEROBIC EXERCISE

Anaerobic means “without oxygen”.

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The anaerobic energy system, particularly the lactic acid system, is the body’s method of rapidly producing energy by the mitochondria and stored in a small molecule called adenosine triphosphate or ATP, without requiring the presence of oxygen-rich-blood.

Mitochondria are membrane-bound cell organelles which generate most of the chemical energy needed to power the cell's biochemical reactions, and can be found abundantly located in the subsarcolemmal or intermyofibrillar regions of muscle cells.

>> Glucose and glycogen – the body’s energy fuel

Glucose is the source of fuel for our cells and what the body uses for energy. In a nutshell, the carbohydrates (complex and simple sugars) we consume are broken by acids and enzymes, releasing glucose, which goes to our intestines where it’s absorbed and passed into our bloodstream. When it is no longer needed for energy, the body creates glycogen from the “leftover’ connected glucose molecules and stores it in the liver and muscles. 

Glycogen is stored in muscles (approx. 80%), in the liver (in high concentration in relation to storing size) and other tissue like heart and brain. Unlike the liver, muscles are unable to release glucose from glycogen into the blood (due to lack of glucose 6-phosphatase). Therefore, glycogen stored in muscles is mainly as a local energy substrate, most often used for short, intense bouts of exercise like sprinting or strength training.

It is also important to know that the body cannot convert fat into glucose to a significant degree. Thus, in the absence of carbohydrates and, consequently, without the primary source of glucose, the body is forced to break down its protein tissues to make glucose for energy, which can lead to muscle loss. Fat is instead broken down and transformed into triglycerides, which are stored in adipose tissue. When glucose levels are low, triglycerides can be converted into acetyl CoA molecules and used to generate ATP for energy (through aerobic respiration).

>> RESISTANCE TRAINING – also referred to as “Strength Training”

Resistance Training increases muscle power/strength by making muscles work – or resist - against a weight or force. Different forms of resistance training include using free weights, weight machines, resistance bands and our own body weight. 

“When it comes to fitness, building muscle power has long played second fiddle to aerobic exercise, perhaps because many people [including scientists in the past] think it is simply for bulking up muscle. But strength training could add years of life and protect you from some major killers. Skip it and you could be overlooking one of the best forms of exercise for the body and mind.” (New Scientist Essential Guide No 16)

Since 2011, the UK’s physical activity guidelines instruct that all adults should perform muscle strengthening activities two days a week, at least, as a result of the mounting evidence on the importance of strength training for health purposes.

>> Examples of anaerobic exercise

• Weightlifting

• Calisthenics - strength training using body weight: jumping, squats, etc

• Sprinting

• High-intensity interval training (HIIT)

• Cycling (if sprint mode / spinning)

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>> Working out with weights – bodybuilding vs “toning”

Let’s start by addressing the “elephant in the room”. “TONING” is a marketing term created to appeal to those who do not want to look like professional bodybuilders as a result of weight training. However, muscles cannot be "toned" as their structure can only increase (hypertrophy) or shrink (atrophy).

The scientific - and true - definition of “muscle tone” is as follows: "a state of the muscle and defined by its tension at rest, clinically determined by resistance to passive movement. It refers to the intrinsic resistance to stretch, resulting from the elastic properties of the tendons, connective tissue, and the muscle tissue itself." Muscle tone is a physiological state and not a muscle component which can be altered at will (aside from managing the tightness of spasticity of it and allow for optimal movement with daily stretching).

Resistance training puts a strain on the muscles which then causes the body to repair them (during what it’s called “recovery period”), eventually resulting in increase of muscle fibres. In short, having more muscle fibres will result in increase of strength and muscle size.

What the marketing term “toning” is actually referring to is nothing other than “body-building” or “muscle building” whilst reducing body fat to allow the muscles to become more uncovered, hence visible to the naked eye – which is exactly the sole intent behind “bodybuilding” as a sport. The only difference between the popularised term “toning” and “bodybuilding” is that the former must follow a “toned down” (no pun) training program stimulating muscle mass to increase modestly and not to the same exaggerated size as that of professional bodybuilders. That is all!

>> Benefits of Strength/Resistance Training

• Develop strong bones. By stressing your bones, strength training, unlike cardio exercise, can increase bone density and reduce the risk of osteoporosis. Activities that put stress on bones can nudge bone-forming or bone-remodelling process into action. “The skeleton is a metabolically active organ that undergoes continuous remodelling throughout life. The remodelling cycle consists of three consecutive phases: resorption, during which osteoclasts digest old bone; reversal, when mononuclear cells appear on the bone surface; and formation, when osteoblasts lay down new bone until the resorbed bone is completely replaced.” (National Library of Medicine, USA, Bone Remodelling, 2006)

• Increased muscle mass and strength. Most people, women in particular, who experience the results of strength training feel empowered in many ways. Not only provides improved capability to perform extraordinary and ordinary tasks alike, but also may prevent sharp muscle atrophy in case of illnesses that cause muscle mass waste (e.g. cancers). Being stronger than average could also improve fighting chances during serious illnesses and treatments and even contribute towards prolonging life span.

• Brain power. Even though the underlying mechanisms aren’t fully understood by scientists yet, strength training seems to trigger the release of several substances - including the protein BDNF (brain-derived neurotrophic factor or abrineurin) which behaves as a neurotransmitter and is key in the support of neurogenesis, neuroprotection, and neuroplasticity - supporting the health of neurons and helps them to communicate, grow and resist age-related decline.

• Weight Management/Fat Loss. Strength training can help you manage or lose undesired weight (excess fat). Increasing muscle mass will result in extra energy (calories) to fuel muscle tissue maintenance and repair. The upsurge in required energy lasts three days after a workout. So, two workouts per week (20 minutes each), need 2 x 200 extra calories (depending on intensity it can be more) to perform and post workout a further 100 extra calories per day (over 3 days) are required to help repair muscle tissue. This means that two workouts a week for 1 month will have required a usage of 5,000 extra calories in energy.

• Enhance quality of life. Strength training may enhance quality of life and improve the ability to do everyday activities, not to mention being a boost to self-confidence. Strength training can also protect joints from injury and contribute to better balance, reducing risk of falls, which is especially beneficial for older adults to maintain a higher level of independence.

• Manage chronic conditions. Strength training can reduce the signs and symptoms of many chronic conditions, such as arthritis and back pain, as well as some of the same cardio training can like obesity, heart disease, depression and diabetes.

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*N.B.: physical exercise must be part of a healthy lifestyle, which must also include a healthy diet and not using harmful substances (ex. tobacco, drugs and excessive consumption of alcohol).