WHAT DETERMINES MUSCLE STRENGTH

​Besides muscle mass, there are many other factors that affect muscle strength. You might have seen people who look "weak", but when they start picking up heavy things you get surprised at how they are able to achieve such feats of strength considering the size of their muscles and body stature.

​And there are opposite examples as well - bodybuilders (people whose goal is to maximize muscle mass) who get overpowered by much smaller power lifters (people whose goal is to maximize strength) for example. 

Here are some videos showing amazing feats of strength by people who might not look like being capable of moving such heavy weights:

Cheryl Anderson (bodyweight 97 ibs) lifting 315 ib

​Weightlifter Chen Wei-Ling (bodyweight 100 ibs) squatting 440ibs ​

​Jennifer Thompson bench pressing 315ibs

​17 Year-old outpeforming many professional athletes.

​​Man bench pressing 410 ibs at 154ibs bodyweight

So what makes this people so strong? Here are 7 main factors that determine muscle strength:

• Muscle mass – all other things being equal, a bigger muscle is a stronger muscle;                                   
• Muscle fiber type – difference in muscle fiber types can explain up to 10% difference in muscle strength. However, someone with a higher proportion of fast twitch fibers can produce much faster muscle contractions;
• Muscle fiber pennation angle – muscle fibers pull on tendons which then transmit force on to the bones. Muscle force will depend on an angle at which muscle fibers pull on the tendons, with more oblique angles contributing to less force. This angle will change depending on the training performed;
• Bone lengths – everything else being equal, someone with a longer bones will have a harder time lifting heavy weights due to a longer gravitational lever length. Think about seesaw – moving away from the middle (the fulcrum) will help you lift the person on the other side.
• Motor control – strength is very specific to the task you are performing. In other words, if you only performing squats, you will get stronger at performing squats, but that doesn’t mean that you will get much stronger at other movements. With practice, you body becomes more efficient at moving heavy weights for that specific movement;
• Motivation –your strength will be completely different when you are not feeling well or tired, compared to when you are well rested and focused on training;
• Muscle attachment sites – our bodies move by pulling bones together which is performed by muscles. Muscles attach to bones, and depending on the distance between the muscle attachment sites, muscle strength (i.e. torque) can vary to a great degree;

So when comparing two individuals, it is important to take into account all of these factors. Muscle mass play a big role in strength, but there are other factors that might contribute even to how strong you are (e.g. muscle attachment sites). ​