Adaptation is the process that the body goes through to improve the functioning of a specific system in order to meet the demands placed on it. The body will adapt to the stresses that are applied. Adaptations can be positive or negative. Positive adaptations occur when stresses is appropriately applied and usually produce an improvement in skill performance and/or physiological status. Negative adaptations are often the result of improper training to include overtraining, undertraining and detraining and are associated with a decrease in skill performance and/or physiological status. There are two general types of adaptation, acute and chronic. Acute adaptations usually occur immediately following and during the first 3 to 4 days post-exercise. Chronic adaptations occur over time, usually after weeks, months and years of training.
You can’t force adaptation (improvement). Regardless of whether you are working to improve a sport-specific skill like fielding, hitting and pitching or physical attributes like flexibility, strength, speed and power, adaptation takes time. The human body is not a microwave oven. Improvements don’t occur instantaneously. Significant improvements in skill and performance take a lot of time. Some say as much as 10,000 hours (1). Ten thousand might not be an accurate value for all skills, but we know that improvement takes time. Research on athletes, for example, indicate that skill performance usually gets worse before it gets better when you change technique (2). These findings explain in part, why it usually takes so long, if ever, for young, talented athletes to develop into Major League performers.
Improvements (adaptations) in physical attributes also take time and every attribute requires a different amount of training time before improvements begin to appear. A brief overview of the time requirements for some of the physical attributes needed for successful, injury-free performance is presented below.
Strength. The NSCA says that it takes a beginner with little or no supervised strength training experience approximately 2-3 months to make significant improvements in muscle size and strength (3). The acute improvements that we see after the first 2-3 weeks of training are the result of nervous system adaptations, not increases in muscle size. Initial improvements occur because the nervous system adapts to training by becoming more efficient, i.e., the body learns to turn on more muscle fibers and to turn them on more quickly. Increases in strength due to actual increases in muscle size takes about 3-6 weeks, with additional improvements (adaptations) requiring another 6-7 weeks of consistent training.
Several factors determine how quickly an athlete will gain strength and how much he/she will improve. Young, inexperienced athletes will a higher ceiling for improvement will improve faster and gain more than older, experienced athletes who are closer to achieving their maximum strength potential. All athletes, regardless of age and experience can continue to improve strength throughout their careers provided they train properly and use the right combinations of intensity, frequency, duration, rest and recovery.
Speed and Agility. Training programs for speed and agility target the central nervous system and are designed to improve communication between the brain and muscles so that the brain can activate a greater percentage of muscle fibers and fire them with more speed and power. Because the CNS has the capacity to respond quickly to new stimuli, acute benefits can often occcur in 1 to 2 days. Chronic improvements in speed and agility, however, take a little longer. It takes at least 8 weeks to see significant improvements in speed and agility when training sessions are held 3-4 times per week and longer with less frequent training sessions.
Flexibility. Improvements in flexibility also take time to develop. Flexibility is not something that happens overnight, nor is it something that can be improved faster by trying harder. And, there is no such things as “general” flexibility. Flexibility is joint-specific and it takes time to improve range of motion and flexibility across multiple joints. Experts say that “flexibility is improved day-to-day” and that it can take at least 2-6 months for most, and as long as 12-months for many, to see the results of daily flexibility training.
Aerobic Capacity. Acute adaptations in aerobic fitness occur after approximately 14 days, depending on the type of training stress (workout) applied. The acute benefits of long, slow distance (LSD) training take longer to appear, sometimes up to 4 to 6 weeks. The delay in improvement is attributed, in part, to an increase in the production cortisol and decrease muscle protein associated with prolonged endurance activity. Faster acute adaptations (7 to 10 days) tend to occur with shorter duration, higher intensity work such as tempo and interval training.
Significant chronic improvements in aerobic fitness take a minimum of 8 weeks to occur. Why so long? Before the body can take in more oxygen and utilize it more efficiently, multiple cardiorespiratory changes have to happen. Improvements in heart rate, blood pressure, stroke volume, capillary density, minute volume ,breathing rate and metabolic pathways must be made before aerobic fitness can be enhanced and each requires a unique amount of time to develop.
Adaptation takes time and requires a unique, progressive training plan for each system of the body (nervous, muscular, cardiorespiratory, oxygen transport, etc.). They system used in the system trained, so there is no one “universal” workout that will improve every system and every physical attribute needed to excel in any sport. Training must be specific and progressive in order to produce the adaptations (improvements) needed. Practicing everything makes you better at nothing. If you are always doing something different, how can you know if you are improving at the thing(s) needed to improve performance and reduce the risk of injury?
The keys to successful adaptation are specificity, consistency, variety, rest and recovery. Workouts have to be specific to the sport of baseball. They must enhance the movement utilized in game situations. They must also be progressive, i.e., each workout must build on the previous. Athletes should work on the same thing, but progress on what they did last week, last moth and last year. Variety is important in order to avoid plateaus, prevent boredom and reduce the risk of overtraining. Rest and recovery are two of the most important and overlooked variables in training. “Work and rest are both important and neither is beneficial with the other”. Work provides the stimulus needed for improvement, but improvements occur during recovery. The rate and amount of adaptation (improvement) produced by the training program will be enhanced or limited by the amount of rest and recovery provided during and between workouts and training phases.
- Gladwell, M. Outliers: The Story of Success. Little, Brown and Company, 2008.
- Godin, S. The Dip. Penguin, 2007
- Baechle, T. and R. Earle. Essentials of Strength Training and Conditioning, Human Kinetics, 2008.
Gene Coleman, Ed. D., RSCC-E, FACSM, was the Head S&C Coach for the Houston Astros from 1978-2012 and is currently a strength and conditioning consultant for the Texas Rangers and Professor in Exercise and Health Sciences Programs at the University of Houston-Clear Lake.