Presentation on theme: "Bone, Muscle, and Connective Tissue Adaptations to Physical Activity"— Presentation transcript:
1 Bone, Muscle, and Connective Tissue Adaptations to Physical Activity
2 Functions of BoneSupport: bone provides a framework for the body by supporting soft tissues and providing points of attachment or most of the skeletal muscles.Protection: bones protect many internal organs from injury very well, such as the brain and spinal cord. In addition, the heart, lungs, and reproductive organs are given some degree of protection.Movement: most skeletal muscles attach to bones. When the muscles contract, they pull on bones to activate lever systems, and movement is produced.
3 Functions of BoneMineral Homeostasis: bone tissue stores a number of minerals, particularly calcium and phosphorus. Under control of the endocrine system, bone releases the minerals into the blood or stores the minerals in bone matrix to maintain critical mineral balances.Blood Cell Production: in all bones of the infant and certain bones of the adult, a connective tissue known as red marrow produces blood cells by the process of hematopoiesis.Storage of Energy: in some bones, yellow bone marrow stores lipids, creating an important energy reserve for the body.
4 Anatomy: Structure of Bone Diaphysis: shaft or long main portion of a bone.Epiphysis: end of a long bone. The two ends together are called the epiphyses. Each epiphysis is covered with articular cartilage.Metaphysis: the region of mature bone where the diaphysis meets the epiphysis
5 Anatomy: Structure of Bone Epiphyseal Plate: In a growing bone, the epiphyseal plate is formed of hyaline cartilage divided into four zones of cells. Under the influence of growth hormone, the plate continues to grow, giving length to the bone. When bone growth exceeds cartilage growth, beginning at puberty, the epiphyseal plate is slowly lost. Growth of long bones stops when the cartilage is completely gone.
6 Anatomy: Structure of Bone Articular Cartilage: covers the surface of bones forming a synovial jointMedullary Cavity: The medullary (marrow) cavity is the space within the bone containing either red or yellow bone marrow. Red bone marrow consists of blood while yellow marrow consists of adipose tissue.
7 Anatomy: Structure of Bone Two Types of Bone Tissue:Compact or Cortical Bone: it forms the external layer of all bones, providing protection and support and helps the long bone resist the stress of weight applied to them. Contains the Haversian system which is composed of bone cells, nerves, blood, and lymph tissue. Spongy Bone: the porous inner layer of bone; found at the ends of long bones and is less dense than compact bone. Contains red bone marrow.
9 Bone MarrowBone marrow is soft fatty tissue found inside the long bones of the body. It contains the following:Red Marrow: red and white blood cells and platelets.Yellow Marrow: fat and connective tissue and produces some white blood cellsPeople are born with only red bone marrow. As a person matures, the red marrow in many of the bones is replaced by yellow marrow.By adulthood, only about half of the bone marrow is red.Red bone marrow is found mostly in the ribs, breastbone, shoulder blades, collarbones, hip bones, skull, and spine
11 Bone Growth and Remodeling Ossification: bone growth due to an increase in bone cellsLongitudinal growth occurs at the epiphyseal plate (cartilage at the end of the long bone)Bone is very dynamic and metabolically activeIt adapts to mechanical loads placed on it through a process called bone remodeling
12 Bone RemodelingBone Remodeling: ongoing replacement of old bone tissue by new bone tissue. It occurs as a delicate balance between bone resorption (removal of old bone) by osteoclasts and bone formation by osteoblasts. It is responsible for bone strength throughout our life.
13 Bone Remodeling Cells Three types of bone remodeling cells: Osteoclasts, Osteoblasts, and Osteocytes.Osteoclasts:Bone destroying cells that cause resorptionOsteoblasts:Bone forming cells that secrete collagenOsteocytes:Mature osteoblasts that regulate bone remodeling
14 Bone RemodelingDuring childhood and the beginning of adulthood, bone becomes larger, heavier and denser, bone formation is then more important than bone resorption.In older adults, bone resorption is greater than bone formation, resulting in a reduction in bone mineral density
15 Bone MassBone Mass: amount of bone tissue in the skeleton, can keep growing until age 30. At that point, bones have reached their maximum strength and density, known as Maximal Peak Bone Density.During childhood and adolescence, much more bone is deposited than withdrawn which makes it the best time to "invest" in one's bone health.
16 Factors Affecting Peak Bone Mass Gender: peak bone mass tends to be higher in men than in women. Before puberty, boys and girls acquire bone mass at similar rates. After puberty, however, men tend to acquire greater bone mass than womenHormones: estrogen has an effect on peak bone mass.Nutrition: calcium is essential for bone health
17 Factors Affecting Peak Bone Mass Physical Activity: girls and boys and young adults who exercise regularly generally achieve greater peak bone mass than those who do not. Women and men age 30 and older can help prevent bone loss with regular exercise. The best activity for your bones are exercises that force you to work against gravityWeight training, walking, hiking, jogging, climbing stairs, playing tennis, dancingLifestyle: smoking has been linked to low bone density
18 Regulation of Bone Remodeling The hormones parathyroid hormone (PTH) and calcitonin (CT), as well as Vitamin D, are the principal regulators of blood calcium concentrationsParathyroid Hormone increases:Bone resorptionCalcium reabsorption by the kidneysAbsorption of calcium by the small intestine(in conjunction with vitamin D)
19 Regulation of Bone Remodeling Vitamin D:Tends to increase the recruitment of osteoclasts, and also plays a part in the mineralization of bone matrix.A lack of Vitamin D results in osteomalacia (impaired mineralization) and too much Vitamin D entails bone loss. Many other important factors are involved in bone remodeling such as estrogen, progesterone and androgens (anabolic hormones)
20 Bone Repair Hematoma formation (clot formation) Callus formation: mass of tissue that forms at a fracture site and connects the broken ends of the bone.Blood vessels grow into clot in hematoma.Macrophages (white blood cells) clean up debrisOsteoclasts break down dead tissue, fibroblasts produce collagen and granulation tissue.Cartilage is produced within the collagenOsteoblasts invadeNew bone is formed.Osteoblasts continue to work on outside of boneBone/cartilage collar stabilizes two pieces
22 Connective TissueA tissue that connects, supports, binds, or separates other tissues or organs. Mostly made up of collagen.Examples of Connective Tissue:BoneTendonLigamentCartilageFat
23 Collagen Most abundant protein in our body Main protein in connective tissueThere is no organ or tissue which does not have collagenResponsible for skin elasticityIt is also used in cosmetic surgery, for example lip enhancement
24 Tendon Tough tissue that connects a muscle with a bone. Tendons transfer the tension created by the muscle to the bone, causing movement.Collagen forms most of the tendonTendon has a direct blood supply, but not very metabolically active because it contains very few cells.Slow to heal
25 Ligament Connects bone to bone providing support to the joint Contains collagen and the protein Elastin which allow ligaments some extensibility.Ligaments have a direct blood supplySlow to heal
26 CartilageRubbery, fibrous and dense, harder than ligaments, softer than boneFound on the ends of bonesShock absorberAids in attachment of muscles to the skeleton,Provides a smooth articulating surface preventing two ends of bones from rubbing together and gratingLacks a blood supplyRelies on synovial fluid for nourishment
27 Stimulating New Bone Formation Minimal Essential Strain (MES):Threshold stimulus that initiates new bone formationMust be weight bearing activitiesIf force reaches or exceeds this threshold, osteoblasts go to that region of bone and secrete collagen.If a large force is applied to the bone, the bone must be able to handle the force.1/10 of the force required to fracture a bone.
28 How to Stimulate Bone Formation Specificity of LoadingExercise SelectionProgressive OverloadTraining Variation
29 Specificity of Loading Selecting exercises that directly load a particular region of the skeletonWalking and running loads the spine, pelvic girdle, femur, tibia, and fibula
30 Exercise SelectionSelecting exercises that incorporate many muscle groups, are multijoint, load the spine and hips, and allow for greater loadsSquat, DB Chest Press, Lunge, DB Shoulder PressSingle joint exercises should be limited
31 Progressive Overload and Training Variation Gradually overloading connective tissue as they become accustomed to the stimuliPlacing greater than normal demands on bodyTraining VariationUse a variety of exercises to stimulate new bone formationMB Lunge, BB Front Squat, DB Step-Up
32 Mechanical LoadingMechanical loading creates deformation of specific regions of the skeleton by bending, using torque, or compressing forces created by muscular contractions on the tendinous insertion of a muscle into bone.Components include:Magnitude of Load: intensity (weight)Rate of Loading: speed (tempo)Direction of Forces: changing the joint angleVolume of Loading: reps x sets x intensity
33 OsteoporosisA loss of bone mineral density which results in weak bonesMay lead to abnormally porous bone that is more compressible like a spongeThe most common sites for fractures are the hip, spine, and wristWhen estrogen levels drop after menopause, bone loss accelerates, which is the major cause of osteoporosis in women
34 Risk Factors For Osteoporosis FemaleCaucasianThin and small body frameFamily history of osteoporosisCigarette smokingLack of weight bearing exerciseDiet low in calciumVitamin D deficiencyExcessive alcohol consumptionChemotherapy
35 SummaryWeight training can increase skeletal muscle mass, force, and metabolic capacity.The extent of tissue adaptation (connective tissue) is related to the degree of deformation primarily by Intensity of training.Stronger muscles pull harder on their bony attachments and cause an increase in bone mass and collagen