Training Stress Score (TSS), Training Stress Balance (TSB) and Chronic Training Load (CTL) are objective vs. subjective metrics found in the WKO software. It is important to note that over-reliance on these metrics, or hitting a particular numeric goal, is not always a good process. These scores are very useful for evaluating how much training stress your body has handled in the past, and/or how stressful a particular workout was.
In short, they are a big picture of ongoing training volume. These metrics are particularly useful to athletes that tend to over train. You must balance the subjective (how you are feeling) with the objective (how you are performing) in order to optimize your training volume.
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Perhaps one of the best ways to evaluate whether or not you have tipped the stress/recovery scale too far in the wrong direction is the inability to complete a particular workout objective. If your training is general (i.e. run 6 miles), this will be difficult to qualify, as there is no particular performance goal to achieve. But your ability to hit a specific wattage target, pace, split or heart rate zone gives you something to hang your hat on. To slightly underperform will mean that either the bar was a bit too high or that you have too much residual fatigue built up to hit the mark.
If you are consistently missing your targets over several days, it is a clear indication that something is not working and needs to be adjusted. Be aware that the more you try to push through another mediocre workout, the more you are tipping the scale toward the need for greater recovery. String enough of these workouts together and you may peak too early or require multiple weeks or more of recovery/reduced volume in order to shake out the accumulated fatigue.
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The amount of time you have to train must align itself with your goals, or you are setting yourself up for failure. Training for an iron-distance race is not going to be possible on just 10 hours per week. It is important to examine your life in totality before signing up for an ultra-endurance event.
I have often said that the greatest value of a coach is to be the objective party that forces an athlete to recover—thus realizing fitness vs. degrading performance. A highly motivated, Type A athlete can be his or her own worst enemy. Training must be a fluid and adaptable process in order to be accurate. The communication between coach and athlete must also be of high quality in order to get the best performance out of the athlete. Too much emphasis can be placed on a set-in-stone training plan.
The best plan is not only the one that addresses the athlete's individual needs specifically, but one that is also flexible in adjusting volume based on how the athlete is responding. I often have several athletes training for the same race, yet their training plans are very different based on a variety of criteria.
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Think of your body as a sponge. It will continue to absorb training volume until it reaches a saturation point. Once the sponge is saturated, it can no longer soak up volume; you are only wasting your energy, risking injury and further degrading your performance. You must let the sponge dry out before it will soak up more fitness and that will require time and patience.
If you are following a pre-built plan, realize that this is somewhat of a hit or miss approach. If your goal is to simply complete a race, you are only training one fitness substrate—endurance—and it is a relatively simple process to build enough to get to the finish line. However, once you start shooting for a PR, the equation becomes a lot more sophisticated.
You must monitor for signs of over-reaching/over-training and adjust your volume, even if your plan requires a certain amount of hours. If you have a high level of muscle soreness, fatigue, low motivation and are experiencing a lot of work stress, a day off may be more effective training than slogging through another mediocre "wet sponge" workout.
More: How to Tell When You're Over-Reaching or Over-Training
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