 Resistance exercise is active exercise in which muscle contraction is resisted by an outside force. This outside force may be manual or mechanical.

 Regular resistive exercise is associated with several positive adaptations which is dosage dependent.  These changes include:

 Acute adaptations are changes that occur in the body during and shortly after an exercise bout.  Chronic adaptations are changes in the body that occur after repeated training bouts and that persist long after a training session is over

 Early strength gains are often attributed to so called neural factors  It is believed to be the dominant influence in the 1 st to 2 nd month of a training program  Assumption from increased EMG amplitude measured during maximal contractions  Co-contraction – refers to the simultaneous activation of an agonist or antagonist during a motor task

 Happen prior to structural changes  Increase in muscle recruitment (71% in untrained)  Increase in firing rate  Increase in the timing and discharge during high intensity muscular contraction  Increase in hypertrophy  Lower activation threshold  Increase in inhibition of antagonist (via GTOs) The Golgi Tendon Organ ◦ § Cocontraction  Increase in Neuromuscular Junction  Increase in Cross-education ( Cross education is a neurophysiological phenomenon where an increase in strength is witnessed within an untrained limb following unilateral strength training in the opposite, contralateral limb. Cross education can also be seen in the transfer of skills from one limb to the other. ◦ § Up to 22% ◦ § Greater EMG

 Bilateral deficit(The bilateral deficit is a phenomenon where the total force production of a bilateral lift (i.e. a squat, deadlift) will not be greater than the sum of individual efforts of a single limb.  Stretch Reflex  Increase in spindle fiber activity by 19-55%  Motor units are recruited according to their threshold of firing rates  Larger loads, greater muscle fiber recruitment  The technique of recording electrical events Electromyography EMG  The process of skeletal muscle activation involves action potential generation on the muscle cell membrane via acetylcholine release from the alpha motor neuron that innervates a particular muscle cell  The action potential is manifested as a voltage change on the sarcolemma that can be recorded with either surface or intramuscular electrodes

 The primary adaptation of skeletal muscle to long-term resistance training is hypertrophy, or increased cross sectional area (CSA) of a muscle fiber, resulting in increased force and power production  During and immediately after resistance exercise, metabolites accumulate and fuel substrates are depleted; thus, clients need to include adequate CHO in their diets

1. Increase in CSA 2. Due to in increase in synthesis and decrease in degradation of contractile proteins 3. Increase in the number of myofibrils within a fiber 4. Resistance training can alter up to 70 different genes ◦ § Increasing regeneration ◦ § Down regulation of inhibitory growth factors 5. Protein synthesis is increased up to 48 hrs following RT 6. Depends on availability of Carb, Pro, and Kcal ◦ § As well as nutrient timing, cell hydration, and mechanical stress of the RT

7. Fiber damage and disruption stimulate synthesis as well 8. Increases are seen in both Type I and II fibers ◦ § Minimal in Type I 9. Athletes who generally possess a relatively large proportion of Type II may have a greater potential for increasing muscle mass with RT 10. We see a shift in fiber type due to RT

1. An increase in the number of fibers ◦ § Via longitudinal fiber splitting ◦ Hyperplasia is different from hypertrophy in that the adaptive cell change in hypertrophy is an increase in cell size, whereas hyperplasia involves an increase in the number of cells. 2. Shown to occur in animals 3. Debated in humans

 Change in ATP and CP concentration seem to be very sensitive to the training mode…  High volume resistance training may induce glycolytic enzymatic adaptations that increase muscle endurance

 Hormones are blood-borne molecules that are produced ion the glands called the endocrine glands.  Anabolic – stimulate growth ◦ ± Catabolic – tissue degradation to help maintain homeostatis

 Osteoporosis – is the consequence of long-term net demineralization of bone  The greater the bone mass prior to menopause, the less severe are the consequences of loss of bone mass. Resistance training may lead to decreased risk for osteoporosis, fractures, and falls in later life

 Osteoblasts ◦ New bone on Periosteum  Osteoclasts ◦ Cells that break down bone ◦ Decreased activity decrease bone mineral density  Stress is needed for bone to remodel ◦ Minimal Essential Strain

 RT causes deformation of specific skeletal regions  Types of force from RT ◦ Bending, compressive, and or torsional

 Osteoblasts migrate to the area of stress ◦ Secrete proteins into the space between cells and increase the bone matrix ◦ Sensitive to mechanical loading ◦ Increases diameter and strength of the bone  The threshold for new bone growth must be met by the force generated by RT  Increase in muscular strength and hypertrophy cause and increase in force exerted on the bone ◦ Causing a direct correlation with Bone Mineral Density BMD and muscular strength and hypertrophy ◦ Starts within first few sessions but is a long process

 Given the clear effect of resistance training on Fat free mass (increase) and its possible effects on resting muscle metabolic rate, resistance training should be a critical component of any comprehensive program to control body fat.

 Increase in Fat Free Mass (FFM)  Decrease in subcutaneous fat  Caloric intake and metabolism are factors  Cardiovascular exercise, Short term is more effective in decreasing body fat

 Specificity of loading should be used to target specific sites  Jumping will not cause a BMD increase in the ulna  The higher the impact the greater the BMD increase will be  Overload progression must be followed To fast will cause stress fractures  Ideal to increase peak bone mass in early adult hood

 a. Intensity  b. Speed  c. Direction of force  d. Volume of force

Structural component of all is collagen fiber ◦ a. A protein ◦ b. Derived from parent protein procollegen from the fibroblasts Stimulus for growth is the mechanical forces created during RT ◦ a. The degree of adaptation is proportional to the force applied during RT ◦ b. Needs to exceed threshold of strain

Increases strength and load bearing by ◦ a. Increasing the junction between the tendon or ligament and bone surface ◦ b. Increasing the strength of the body of tendon or ligament ◦ c. Increasing the network of fascia within the skeletal muscle

 Stronger muscle pulls with greater force on their bony attachments causing in increase in bone mass at the tendon bone junction

 Increase in collagen fibril diameter  A greater number of covalent cross links within the hypertrophied fiber  An increase in the number of collagen fibrils  An increase in the packing density of collagen fibrils ◦ RT increase tendon stiffness  Only with heavy loads of 80% RM

Function ◦ Provide smooth joint articulating surface ◦ Act as shock absorption ◦ Aid in attachment of connective tissue Does not have its own blood supply ◦ Gets nutrients through diffusion from synovial fluid RT will increase the thickness of the cartilage that experiences weight bearing ◦ The heavier the thicker

 Resistance training with aerobic endurance training can improve the ability of the heart, lungs, and circulatory system to function under conditions of high pressure and force productions Acute (exercise)  Increase in ◦ § HR ◦ § SV ◦ § Q ◦ § BP  Have seen peaks of 320/250 mmHg an 208 b/m during high intensity RT Chronic while RT  Blunted increases in HR and BP

 Ventilation generally does not limit RT  At most moderately improved by RT  Unless RT is done as a circuit ◦ Ventilation levels are highest directly following the performance of an exercise ◦ ± Some increases have been seen in tidal volume and breathing frequency as well as ventilation equivalent

 ± Adding aerobic training to RT will decrease the ultimate effects of RT  o Strength power and hypertrophy  ± Most studies have shown no adverse effects of adding RT to aerobic training  ± With the combination of Aerobic and Anaerobic the risk of overtraining is increased

 1. Specificity  2. Sex  3. Age  4. Genetics

 overtraining is a physical, behavioral, and emotional condition that occurs when the volume and intensity of an individual's exercise exceeds their recovery capacity. They cease making progress, and can even begin to lose strength and fitness.  Overtraining is a common problem in weight training, but it can also be experienced by runners and other athletes.

 Plateau followed by a decrease of strength gains  Sleep disturbances  Decrease in lean body mass  Decreased appetite  A cold that doesn’t go away  Flu like symptoms  Loss of interest  Mood Changes  Excessive muscle soreness

Detraining refers to the bodily effect experienced when one takes an extended break from regular, vigorous fitness training. Fitness levels and muscle mass can decline during a break that lasts between two and four weeks. While this sort of long-term break may reduce current fitness levels, it may also offer long-term benefits if the person starts retraining, allowing them to achieve higher levels of fitness than before detraining.  Atrophy in the fast-twitch muscle occurs faster