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Resistance training increases muscle strength by pitting the muscles against a weight, such as a dumbbell or barbell. The muscle cells adapt to the extra workload by enlarging (hypertrophy) and recruiting greater numbers of nerve cells to aid contraction. Understanding the principles of muscle contraction can help you reach your musculoskeletal (muscle and skeleton) fitness goals faster.
It is important to pay attention to safety and good form to reduce the risk of injury. Undertaking some form of bodyweight training that builds a foundation of strength, and strengthening of the deeper stabilising muscles, before moving to formal resistance training could be beneficial.
Consult with your doctor before starting any new exercise program, especially if you are overweight, over 40 years of age, have a pre-existing medical condition or haven’t exercised in a long time.
Benefits of resistance training
The benefits of regular resistance training include:
- Increased muscle strength, power, endurance and size
- Increased bone density and strength
- Reduced body fat
- Increased muscle-to-fat ratio
- Boosted metabolism (burning more kilojoules when at rest)
- Lowered heart rate and blood pressure after exercise (thought to reduce the risk of heart disease)
- Improved balance and stability
- Enhanced performance of everyday tasks
- Reduced risk of, and improvement of, medical conditions – for example, diabetes (NIDDM) and arthritis.
Maximal voluntary contraction
Maximal voluntary contraction (MVC) means the muscle has contracted to the best of its ability. In resistance training, MVC is measured by a formula known as XRM. ‘X’ refers to the weight that can be lifted x-amount of times before muscle fatigue sets in. RM means ‘repetitive maximum’ and refers to the number of times the contraction can be performed. The formula 7RM means the person can lift the weight (let’s say it’s 50kg) seven times before the muscles are too fatigued to continue.
Higher weights mean lower RM – for example, the same person could lift a 65kg weight perhaps three times. Lower weights mean higher RM – for example, the person could lift a 35kg weight about 12 times before muscle fatigue set in.
Applying MVC to meet your fitness goals
Once you understand the principle of MVC, you can get the maximum benefit from your resistance training. Guidelines differ depending on your experience, but generally include:
- Muscle power – one to six RM per set*, performed as quickly as possible.
- Muscle strength/power – six to twelve RM per set.
- Muscle strength/size – six/eight to 12 RM per set.
- Muscle endurance – 10 to 15 or more RM per set.
(*A ‘set’ means the number of repetitions you perform in a row before having a rest.)
The physiology of strength gain
Most beginners experience a rapid increase in strength, followed by a ‘plateau’ or levelling out of their strength improvements. After that, gains in muscle strength are hard earned.
When you start resistance training, your initial increase in strength is due to a phenomenon called ‘neural adaptation’. This means that the nerves servicing the muscles change their behaviour. The nerves are thought to ‘fire’ more frequently (prompting increased muscle contraction) and more motor units are recruited to perform the contraction (a motor unit is the nerve cell and its associated muscle fibres). This means you become stronger, but the muscles remain the same size.
In time, the muscle cells respond to resistance training by increasing in size (hypertrophy). So don’t be discouraged by reaching the ‘plateau’ – it is actually an encouraging sign that gains in muscle size may soon follow.
Basic principles
The basic principles of resistance training include:
- Type of lift – you need to tailor your workout to address specific body areas or movement patterns. For example, if you want bigger and stronger arms, you need to use exercises that target those particular muscles.
- Intensity – the faster the lift, the greater the intensity.
- Volume – the greater the number of lifts, the more profound the increase in muscle size and strength. You can increase the volume by either training frequently (say, four times a week instead of two) or training for longer each session (such as one hour instead of 30 minutes).
- Variety – switching around your workout routine, such as regularly introducing new exercises, challenges your muscles and forces them to adapt with increased size and strength.
- Progressive overload – gradually increasing your weights forces your muscles to grow stronger and larger.
- Rest – you need to rest between sets. If your goal is muscle size or endurance, rest for two minutes or so. If you want muscle strength, allow up to four minutes between sets.
- Recovery – muscle needs time to repair and grow after a workout. A good rule of thumb is to rest the muscle group for at least 24 hours to allow sufficient recovery time before working the same muscle groups again.
Safety suggestions
General safety suggestions include:
- Only use safe and well-maintained equipment. Faulty equipment will significantly increase your risk of injury.
- Warm up and cool down thoroughly. Incorporate slow, sustained stretches.
- Wear appropriate clothing – natural fibres ‘breathe’ better than synthetics, and multiple layers of clothing are preferable to one bulky layer.
- Don’t forget to breathe – exhale at the point of greatest exertion rather than holding your breath.
- Control the weights at all times – don’t throw them up and down or use momentum to ‘swing’ the weights through their range of motion.
- Make sure you use correct lifting technique. If you are unsure, consult with a qualified gym instructor, exercise physiologist or physiotherapist. Incorrect technique can slow your progress or even cause injuries.
- Ensure you move the weight through your joint’s full range of motion. This not only works the muscle fully, but reduces the risk of joint injury.
- Work out with a partner, especially if you are using heavy weights.
- Balance your training so that you are working muscles on the front and rear of the body. An imbalance in strength between muscle groups can lead to injury.
- Make sure you train the deep stabilising muscles appropriately. These include the rotator cuff in the shoulder and the deep stabilisers of the low back and neck.
Where to get help
- Your doctor
- Qualified gym instructor or personal trainer
- Exercise physiologist
- Physiotherapist
- ‘Go for your life’ Infoline Tel. 1300 739 899
Things to remember
- Resistance training increases muscle strength by pitting the muscle against weight, such as a dumbbell or barbell.
- The muscle cells adapt to the extra workload by enlarging (hypertrophy) and recruiting greater numbers of nerve cells to aid contraction (neural adaptation).
- Consult with professionals, such as your doctor or physiotherapist, before you embark on any new fitness program.
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