WHAT DETERMINES MUSCLE STRENGTH

written by: Nem​
​Besides muscle mass, there are many other factors that influence muscle strength. You might have seen individuals in your gym or online achieving amazing feats of strength who don't appear that strong or muscular.

To give you an example, here are a couple of videos showing amazing feats of strength by individuals who don't appear very muscular:

Cheryl Anderson (bodyweight 97 ibs) lifting 315 ib

Man bench pressing 410 ibs at 154ibs bodyweight

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

Jennifer Thompson bench pressing 315ibs
​

17 Year-old outpeforming many professional athletes.

​Then there are individuals on the opposite end of this spectrum. People who appear very strong and muscular that don't display impressive levels of strength. For example,​ bodybuilders (people whose goal is to maximize muscle mass) often get overpowered by smaller power lifters (people whose goal is to maximize strength).

Whenever I talk to my clients on this topic, I always get reminded of the video when a muscular baseball fan tryies to open a water bottle during a game (video below).

​FACTORS THAT DETERMINE MUSCLE STRENGTH

So what determines muscle strength? Here are 7 main factors that influence 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). ​