Adaptations to Exercise Training

Introduction Exercise training can be defined as participation in chronic, organized physical activity, with the goal of improving athletic performance or specific health and fitness parameters

Principles of Exercise adaptation Specificity of Training –A specific exercise elicits a specific training response Overload Principle –Improvement in performance capacity occur when regular physical activity is increased above the level that the performer usually experiences –Three factors FrequencyIntensityduration

The Principle of Individual Differences –No two individuals are the same –Unique motor performance profile, and training strategies may need to be customized to match the individual’s rate of improvement

Types of Anaerobic Exercise Training Increases in muscular strength generally require exercise intensities of least 30% of maximal voluntary contractile strength (MVC) Isometric Exercise –No change in joint position –Desirable in some rehab. situation –Little or no equipment –Can be done almost anywhere –Better to perform at various joint angles 35 ° 45 ° 55 ° % strength gain Joint angle

Dynamic Resistance Exercise –Changes in muscle length and joint angles –Concentric muscle contractions can offer very forces and thus an appropriate overload stimulus –Eccentric muscle produce more muscular force than that obtained during an isometric muscle contraction –Eccentric or lengthening muscle contractions is both highly fatiguing and highly susceptible to muscle soreness

Assessing Success of Anaerobic Exercise Training Dynamic muscle strength can be estimated using the 1 RM (repetition maximum) Anaerobic power maximum amount of force that can be generated over a period of time –Margaria power test or Wingate cycling terst

Exercise Tests

Aerobic Exercise Training –Low intensity or relatively low force levels –Continuous training One type of aerobic exercise training –Exercise at a low intensity for a duration sufficient for creating an aerobic overload –Workload may be estimated as a percentage of maximum heart rate or a percentage of VO 2max –Aerobic exercise should be performed at an intensity of about 60 to 80% of maximal heart rate

Rating of Perceived Exertion –Borg (1970s) discovered that our sense of effort bears a close relationship to actual workload –Borg’s scale correlates well with heart rate and VO 2 max

Rating of Perceived Exertion

Interval Training –Alternating higher-intensity exercise bouts with rest periods, overload stimuli can be applied that stress the intermediate energy systems and long-term aerobic systems –Major advantage is that more total work can be done by dividing it into several bouts than by performing it continuously

Other Types of Exercise Training Fartlek training –Designed by Swedish exercise –A type of alternating fast-slow training Hollow sprints –Alternate periods of sprint, jogging, and walking

Long-Term Adaptations to Anaerobic Exercise Training Muscle Strength –Muscle strength to increase with long-term resistance exercise training –Initial strength increase can be dramatic –Most of gain occurs during the first month, subsequent gains much more slow, –Strength decrease as detraining persists

–Major part of initial gain in strength originates in the nervous system –Learn how to activate more motor units in the muscles responsible for action or how to activate them more efficiently –Nervous system learns task in a more coordinated fashion

Training the Brain –Thinking about performing a maximal voluntary muscle contraction on a regular basis can improve muscular strength

Muscle Fiber Adaptations Slow twitch muscle fibers are recruited or brought into action first, with the fast twitch muscle fibers recruited as the force increases Fast-twitch fibers to hypertrophy even more than slow-twitch fibers

Long-Term Adaptations to Aerobic Exercise Training An expect of VO 2max to increase as the aerobic training program progress Increase the efficiently of the oxygen utilization system Respiratory Adaptations –Lung become more capable at extracting from the inhaled air and exchanging it for CO 2

Oxygen-Carrying Adaptations –Increase myoglobin in muscle with endurance exercise, facilitating the delivery of O 2 to mitochondria Blood-Delivery Adaptations –Endurance training increases the size of the heart –Total blood volume increases helps O 2 delivery and regulation of body temperature –An increase in the number of RBC helps to provide more oxygen-carrying hemoglobin –Stroke volume increases with training

Energy Production Adaptations –More mitochondria in the trained individuals –Enzymes for aerobic metabolism increase in concentration and efficiency –Muscle learns to contain more glycogen –Beta-oxidation increases to better use fat stores for energy

Other Aerobic Adaptations –Increase in the proportion of slow-fibers –Increase fatigability of most muscle fibers –Better handle the heat produced

Summary of Anaerobic and Aerobic Training Adaptations The specificity and overload principles are key to understanding and predicting adaptations that occurs with training Floor-and-ceiling effect of hemoglobin

Antagonism between Anaerobic and Aerobic Training –Training aerobically may hinder anaerobic performance and vice versa Strength training decrease muscle myoglobin content Resistance exercise training increase the proportion of fast-twitch muscle fibers

Detraining Once training stops, the positive effects of resistance exercise or endurance training wear off at about the same rate that training occurred

The Space Environment 30 days of space flight, –muscle may atropy as much as 20%, –muscle strength decrease by about 20% –Bone mass decrease about 1 to 2 % per month –Problems in balance and postural control VO 2max can decrease by as much as 25% after 20 day of bed rest

Percent change in gastrocnemius and soleus muscle volume from preflight to postflight recovery days 4 (R+4) and 19 (R+19). *P < 0.05 vs. preflight. †P < 0.05 vs. gastrocnemius. Scott Trappe et al., 2009

Overtraining 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.

Overtraining

General adaptation syndrome –Hans Selye (1950s), stressed and allowed to recover, rats grew stronger, if repeatedly stressed without sufficient time for recovery, rats grew weaker Cure for overtraining –Reduce the intensity, duration, frequency of exercise –Training levels should be increased slowly and regular rest period –Maintain adequate diet and plenty of sleep

Tapering Refers to the practice of reducing exercise in the days just before an important competition. Tapering is customary in many endurance sports, such as the marathon, athletics and swimming. For many athletes, a significant period of tapering is essential for optimal performance. The tapering period frequently lasts as much as a week or more

Tapering

Swimmers decrease their training for 15 days resulted in a 25% increase in muscular power and 4% performance improvement Reducing training volume several weeks before big meet to enhance performance Tapering may be one way of compensating for overtraining during part of the training period

Discussion What biochemical changes may occur each bout during interval training (glucose, lactate etc.) and why. Can you using the University’s campus, (gymnasiums, stadiums, buildings etc.) to plan a Fartlek training (drawing a running course) for distance runner. How do you do to detect subjective and objective overtraining to athletes.