Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Chapter 4 The Skeletal System

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Objectives Understand the anatomy of bone Understand the anatomy of connective tissue Describe Wolffs law Describe training adaptations to bone

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown The Skeletal System Is dynamic with living cells that continually remodel bone tissue Responds through adaptation to specific demands placed upon it through training and conditioning which cause unique adaptations to bones, ligaments, tendons, and cartilage.

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Anatomical Divisions of the Skeletal System Axial skeleton: the skull, the vertebral column, the sacrum, the coccyx, the ribs and sternum Appendicular skeleton: appendages, pectoral girdle and the pelvic girdle

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown

Bone Tissue Osteocytes: bone cells (both osteoclasts and osteoblasts) located in the lacuna –Osteoclasts reclaim calcium for metabolic processes and removing damaged bone –Osteoblasts deposit new bone matrix to replace bone removed by osteoclastic activity

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Bone Tissue (cont.) Cortical bone is highly mineralized, dense, and has a low porosity Trabecular bone is bone that is less mineralized, porous in nature, and therefore less dense

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Epiphysis Epiphyseal disks provide the site where bone increases in length Long bones continue to grow in length up to the time of epiphyseal closure

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Ligament Tissue Tough fibrous tissue with little elasticity Prevents joints from moving in abnormal patterns May allow movement in one plane or restrict movement in an abnormal direction

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Articular Cartilage Covers the ends of long bones and reduces friction at the joint while moving under pressure Consists of a dense mesh of collagen fibrils, proteoglycan macromolecules (PGs), and water creating a stiff gel-like substance

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown

Functions of the Skeletal System Structure and protection Movement Blood cell production –Spongy bone houses the red marrow that produces blood cells

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Functions of the Skeletal System (cont.) –Production of red and white blood cells is a result of differentiation of mature blood stem cells which reside primarily in the flat bones of the skull, ribs, sternum, and the ends of the long bones. –Every second, the body produces over 2 million RBCs

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown

Skeletal System Adaptations to Loading Wolff’s Law Minimal essential strain

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Wolff’s Law “The densities, and to a lesser extent, the sizes and shapes of bones are determined by the magnitude and direction of the acting forces applied to bone.”

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Minimal Essential Strain Minimum volume and intensity of loading required to cause an increase in bone density Approx. 10% of the strain required to fracture bone is considered the threshold at which new bone formation is triggered

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Skeletal System Adaptations to Loading

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Skeletal System Adaptations to Loading

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown The Skeletal System and Health Appropriate dose of physical activity can increase bone mineral density Higher bone density in the active years, results in greater ability to maintain bone density through the aging process

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Female Athletic Triad An eating disorder (normally anorexia nervosa) accompanied by a distorted body self-image Osteoporosis is the loss of bone mineral density and destruction of associated matrix materials Amenorrhea (irregular or complete absence of menses)

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Exercise Rx to Promote Bone Density 1.Loading speed 2.Rate and frequency of loading 3.Direction of loading 4.Intensity of exercise 5.Frequency of training

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Vibration Changes the direction and flow of intracellular fluid at a rapid rate Experimentation to combat the effects of microgravity using vertical vibrational loading to promote bone strength and BMD gains is ongoing

Chandler/Brown: Conditioning for Strength and Human Performance© 2008 T. Jeff Chandler and Lee E. Brown Next Class Chapter 5 Biomechanics Exam 1 in one week