How do muscles work?

Did you know? Our bodies are composed of over 650 muscles, which can be split into 3 main groups: the cardiac muscles, the smooth muscles (which contract automatically) and the skeletal muscles which enable us to carry out movements through voluntary contractions.


In weight training, the main focus is on the skeletal muscle, which represent around 40% of our total body mass. How do muscles work during a workout? How do muscles grow? How can you implement the most effective training to increase strength and muscle mass? We asked Eva, our sports coach.


How muscles work

Muscles are composed of muscle fibres which are themselves composed of myofibrils, which are the contractile units of your muscles. During a workout, these fibres activate: the muscle shortens, creating a muscle contraction, causing the ends to draw closer together, and thus causing movement. When you weight train, you strain your muscles with extra loads or body weight in order to increase your strength , endurance, or muscle mass.


Muscular hypertrophy mechanism

Without gravity, muscles atrophy, also known as muscle wasting.
Conversely, when muscles are subjected to great tension, they hypertrophy. This is known as muscular hypertrophy. How does it work?


When you lift more weight than your muscles are able to support, weight training places stress on the muscle tissue, causing micro-tears in the fibres. To avoid further damage from this trauma, an overcompensatory reaction takes place to repair the damaged muscle fibres. The muscle then creates new connections between the fibres and then grows stronger and in volume, which enables it to better resist future training.


During training sessions, muscles will lose their strength and volume. This is only because the muscle is recovering, regenerating and developing. Recovery is thus just as important as the training itself!


How do you activate muscular hypertrophy?


When starting weight training for the first time, do not exceed 2-3 sets for smaller muscles, and 3-4 sets for the larger ones. As you progress, gradually increase the number of sets until you reach 5-6 and 6-7 sets per muscle. Allow yourself 1 minute of quiet rest between each set.


Weights and reps

To begin gaining muscle, you need to regularly increase the weight or the number of reps in your exercises. Carry out 8 to 12 reps per set. If you feel able to do 14 or 15, then go ahead! But if you do this, make sure you increase the weight for the next set. Choose the weight according to the number of reps, and not the other way round. For example, if you plan to do a set of 10 reps, choose a weight that will enable to carry out 10 reps, and no more. Don't use a weight that is too light, as the aim is to exhaust your muscles by the end of the 10 reps. Stop when your last reps is slower or less technically well-accomplished than the previous ones.


Working until you suffer from muscle fatigue is not necessary. This technique consists of completely exhausting the muscle by carrying out sets until you are no longer able to carry out the movement. Whilst this method enables more intense workouts, it puts the nervous system under excessive pressure, and increases recovery time.


Training frequency

1 weight training on a weekly basis enables some progress to be seen in a beginner, but the frequency of training needs to be quickly increased to obtain greater results. A minimum of two sessions per weeks is enough to progress, but the ideal is around 3 training sessions per week. Our advice is to never exceed 4 sessions per week in order to avoid over-training. If you do this, you risk exhausting your body and limiting your progress.


3 rules for developing your muscles

Here are 3 tips to help you organise your weight training exercises and get the most from your sessions:

  1. If you're working on both your arms and pecs, back, or shoulders in the same session, finish with the arms to make sure they're not already tired when you work out the rest of your body.
  2. Work both the left and right sides to make sure you remain balanced. Work the agonist and antagonist muscles (a muscles and its opposing muscles: biceps/triceps, pecs/back…)
  3. Try changing which muscle you begin your training session with in order to prevent boredom and keep yourself motivated.




And one last tip: to promote muscular hypertrophy and encourage muscle growth, don't forget to follow a suitable nutrition programme. Your muscles need the right nutrients to develop properly!


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