GR. 12 FITNESS Health Unit 1 Mr. Mackay

MUSCULAR SYSTEM The human body is comprised of 324 muscles Muscle makes up 30-35% (in women) and 42-47% (in men) of body mass. Three Types of Muscle Skeletal muscle Smooth muscle Cardiac muscle

Connects the various parts of the skeleton through one or more connective tissue tendons During muscle contraction, skeletal muscle shortens and moves various parts of the skeleton Activated through signals carried to the muscles via nerves (voluntary control) Repeated activation of a skeletal muscle can lead to fatigue 3

STRUCTURE OF MUSCLE 4 d) myofibril c) muscle fibre b) muscle fibre bundle a) Muscle belly

MUSCLE TEAMWORK Agonist (prime mover): - Muscle or group of muscles producing a desired effect. Antagonist: - Muscle or group of muscles opposing the action. Synergist: - Muscles surrounding the joint being moved. Fixators: - Muscle or group of muscles that steady joints so that the desired action can occur. (Stabilizers) 5

MUSCLE TEAMWORK 6 Bending or straightening of elbow requires the coordinated interplay of the biceps and triceps muscles

MUSCLE PAIRING Bicep-Tricep Pectorials-Rhomboids/Infraspinatus Gluteus Maximus-Illiopsoas Bicep Femoris-Rectus Femoris Gastronemius-Anterior Tibialis Anterior Deltoid-Poster Deltoid Erector Spinai-Rectus Abdominus Tensor Fasciae Latae-Gracilis 7

FAST vs SLOW TWITCH SLOW: Suited for repeated contractions during activities requiring a force output of < 20-25% of max force output. ie: low power activities, endurance events. FAST: Significantly greater force and speed generating capability than slow twitch fibres. Well suited for activities involving high power. ie: sprinting, jumping, throwing 8

MUSCULAR CONTRACTIONS Concentric: Muscle shortens under tension. Eccentric: Muscle lengthens under tension. (Negative) Isometric: Muscle remains the same length under tension. (Flex & Hold) 9