Muscles pairs And other things Three Main Types

Muscles pairs And other things

Three Main Types of Muscel Fibers Slow Twitch oxidative fibers (I) Fast Twitch A (II-A) Fast Twitch B(II-B)

Slow Twitch Oxidative Fibers (I) Oxidative (uses oxygen to create energy) Very fatigue resistant Posture muscles

Fast twitch A (II-A) oxidative rapid contractions relatively fatigue resistant sprinter's legs

Fast twitch B (II-B) >glycolytic rapid contractions easily fatigued >arm muscles

The diagram shows the structure of the muscles. The inset picture (brown colored) shows you the fast and slow twitch fibers. Lighter = fast twitch / darker = slow twitch.

Muscles have opposing pairs • Muscles can only pull not push –So they can only move a bone or joint in one direction. –It requires another muscle to move it back

Who are some common pairs? • Triceps and Biceps -bending and straightening the elbow • deltoids and lattisimus dorsi - lifting the arm and lowering the arm • abdominals and erector spinae- bending the spine forward and backward

A few more groups • hip abductors and adductors - moving the legs apart and together • quadriceps and hamstrings - bending and straightening of the knee • gastrocnemius and tibialis anterior - standing on your toes or pulling your toes up toward your shin

A couple more • pectorals and trapezius - moving the arms/shoulders forward and backward (arms are held horizontal and shoulder high for this movement) • iliopsoas and gluteals- lifting the knee or moving the knee backward

Natural muscle imbalances • Daily use tends to strengthen one part of the pair more than the other –Ex: • Biceps – lift against gravity, therefore they are stronger than triceps. • Turning your head in one direction, or using one arm more strengthens one set of muscles, but can weaken or shorten others

How can this hurt us? • Imbalances can lead to muscle pain –Most lower back problems are from muscle imbalances • one way is abdominal muscles become weak but erector spinae becomes too strong, pulling the pelvis into the wrong position

So, let's work those muscles. . . • But don't forget to work both parts of the pair. –You might also need to work a weaker member of a pair to strengthen it or to stretch it. • If you carry heavy groceries or kids, you might need to work on your triceps.