Stress, Recovery, & Adaptation

The Stress-Recovery-Adaptation (SRA) Cycle describes the change in performance levels across time when a person is subjected to strenuous exercise. It is an adaptation from the General Adaptation Syndrome (GAS) which describes action-reaction processes in physiology. For athletes, or any other goal-oriented exerciser, this cycle is important to understand even if only at an introductory level. This is because many issues with performance-related plateaus (stalled progress) are rooted in a failure to properly program training variables with respect to the SRA cycle. Consider the graph below for further discussion:

Figure 1, “Single SRA Cycle”

A few quick notes. First, it should be noted that this is not a perfect model. There are other “fitness-fatigue” models that have a greater level of nuance; however, the SRA cycle is the better pedagogical tool. Secondly, the terms, “exercise” and “stress,” are going to be used interchangeably here as exercise is a stressor to your physiology. Lastly, “performance” in the SRA model can refer to any measure of fitness (e.g., strength, speed, vertical jump height, endurance).

            Timepoint (TP) #1 is the administration of an overloading exercise session after which performance is temporarily diminished as various measures of fatigue have accrued. TP#2 marks the greatest decrease in performance, and it is after this point that recovery will increase the level of performance back up to the original baseline. Beyond simply recovering to baseline, your physiology attempts to further adapt or “super-compensate” as performance continues to improve beyond baseline towards TP#3. This is physiology’s attempt to become more capable should it continue to encounter this same type of stress again. After TP#3, if the previous exercise stimulus is not repeated, then performance will begin to diminish again towards baseline—TP#4 (short-term detraining). Furthermore, if the original baseline activity is also removed, then performance can even begin to drop below previous baselines of performance (long-term detraining). To recap simply:

->TP#1 = Overloading bout of exercise.

->TP#2 = Greatest decrease in performance after exercise bout.

->Recovery = Subsequent performance increase back to baseline.

->Adaptation = Performance increase above and beyond previous baseline.

->TP#3 = Greatest increase in performance after recovery and adaptation phases.

->TP#4 = Performance’s return to baseline if the stimulus is not applied again (detraining).

            Ideally, exercise/performance training takes advantage of this timeline of events and reintroduces an overloading exercise stimulus at or near TP#3. If this is timed correctly, then TP#3—the height of the adaptation phase—will act as the new baseline and the cycle will initiate again and performance during the following adaptation phase will increase even more greatly than before. This is the entire basis of training for increased performance—timed, repeated bouts of progressively overloading exercise sessions. This timed administration of multiple bouts of exercise is modeled below:

Figure 2, “Timed, Multiple SRA Cycles”

If this cycle continues week after week, month after month, and year after year, you end up with whatever performance measures that you set out chasing whether that be increased strength, vertical jump height, speed, mobility, or endurance. Both of these models (single SRA & cyclic SRA) highlight common errors in training and athletic development:

->Error 1 = No overload is produced. Exercise variables, namely intensity and volume (number of hard sets and repetitions), are too easy and under-challenging. TP#1 must create TP#2 if TP#3 is desired. This also requires overload to be progressive with time and increases in performance.

->Error 2 = Too much overload is produced. Exercise variables—especially volume—are too hard. Excessive overload creates a scenario where resources are focused disproportionately towards recovery and not towards the subsequent adaptation. TP#2 cannot be driven excessively low.

->Error 3 = Recovery and adaptation are not emphasized outside of the gym. Poor sleep and dietary habits can quickly squander performance improvements even if high-quality training is being implemented. The path between TP#2 and TP#3 needs to be augmented by improved lifestyle factors.

->Error 4 = Timing of reoccurring overloading exercise is too delayed. This will result in no long-term progress in performance. Reoccurring stress must be scheduled closer to TP#3 than TP#4 in order for baselines to summate.

->Error 5 = Timing of reoccurring overloading exercise is too soon/frequent. This will result in a decrease in performance due to overtraining and lack of rest (when recovery and adaptation phases occur). Reoccurring stress must be scheduled closer to TP#3 than TP#2 or performance baselines will be driven downward.

->Error 6 = Lack of long-term consistency. Significant adaptations to performance training requires long periods of time—months and years. This means an appropriate amount of overload needs to be implemented (without errors 1 & 2), in a well-timed/scheduled exercise program (without errors 4 & 5), while emphasizing recovery and adaptation phases outside of training (without error 3), with consistency over long durations of a calendar. Without this long-term consistency, significant amounts of performance improvements will not be accrued.

->Error 7 = Poor maintenance of an achieved goal/new baseline. All performance improvements are subject to detraining (i.e., losing them) if the stressors that created the adaptations are completely removed. For many athletes, this means switching to an in-season program. These programs have modified training variables (especially volume) designed to maintain improvements while ensuring very little fatigue is incurred (TP#2). This simultaneously allows the athlete to perform at a high-level while not negatively affecting sport practices and competitions.

In conclusion, the SRA curve is extremely important to understand when designing a program that aims to improve any desired performance outputs (e.g., strength, power, speed, endurance). A lack of understanding will lead to poor program design, subsequent violation of the aforementioned errors, and the inevitable failure to produce the intended progress/results. Lastly, this required precision highlights the difference between goal-oriented “training” versus the random “workouts” that are so common within the fitness industry. Directionless, unplanned, and unstructured programming typical of the average workout will guarantee that you have nothing to show for your efforts.

Takeaway Points:

>The Stress-Recovery-Adaptation cycle should inform many aspects of your training program.

>Lacking a working understanding of the SRA cycle will lead to multiple training errors.

>These training errors are often the reason behind poor results and the lack of performance-related progress.

>Train—don’t just workout—because athletic development is much more than just showing up.