A 100-day break cost more agility than the training block had added
In short
Sixteen women aged 60 and over were assessed five times: at baseline, after resistance training, after a 100-day detraining period, after resistance plus interval training, and after a second 100-day detraining period. Resistance training improved agility and dynamic balance by 12.2%, upper-body muscle endurance by 35.4%, lower-body endurance by 24.6% and gait speed by 8.2%, while handgrip strength and flexibility did not change. The first layoff cost 19.5% of agility and dynamic balance and 21.6% of lower-body endurance; after the interval phase, losses in the second layoff were markedly attenuated.
If you want a number for what a long layoff costs, this is close to it. Agility raised 12.2% by training fell 19.5% across 100 days off. More came off than had gone on.
What was measured, five times over?
Sixteen women aged 60 or over took part. Assessments came at baseline, straight after resistance training, straight after a first 100-day layoff, after a resistance-plus-interval phase, and after a second 100-day layoff. Outcomes covered agility and dynamic balance, upper and lower body muscle endurance, gait speed, handgrip strength and flexibility.
What resistance training moved, and what it did not
The resistance phase improved agility and dynamic balance by 12.2% (p<.001), upper-body muscle endurance by 35.4% (p<.001), lower-body endurance by 24.6% (p<.001) and gait speed by 8.2% (p=.004).
Handgrip strength (p=.860) and flexibility (p=.683) did not change. The program moved what it targeted and left the rest alone, which is a plain reminder that the outcomes you get are the ones you trained for.
What goes first during 100 days off?
The steepest losses after the first layoff were agility and dynamic balance at -19.5% (effect size d=1.44) and lower-body muscle endurance at -21.6% (d=-1.13). Upper-body endurance, which had gained most, was not what collapsed fastest; balance and the lower body were.
Why did the second layoff cost less?
The resistance-plus-interval phase produced partial recovery, most visibly in agility and dynamic balance (d=-0.59), and the second 100-day layoff showed clearly attenuated losses with minimal change overall. The authors conclude that adding interval training was associated with greater retention of functional gains through detraining.
Sixteen participants, all women aged 60 and over, assessed on functional tests rather than 1RM. Because the two training phases ran in sequence, this design cannot separate whether the smaller second-layoff loss came from the interval work or from accumulated training history.
What it means for your Muscle Index
Muscle Index is calculated on the last Big 3 numbers you logged. After months away, the score should reflect the body you have now rather than the one you left, so retest and log soon after coming back. That is also what makes the next layoff measurable on the graph instead of guessed at.
On what disappears first once supervision ends, see strength fades before muscle when you train alone. On managing intensity later in life, see you can still train hard after 50. For rest-day allocation, see one rest day a week is the floor.
Frequently asked questions
How much do you lose after 100 days off?
In 16 women aged 60 and over, the first 100-day layoff cost 19.5% of agility and dynamic balance and 21.6% of lower-body muscle endurance. Agility lost more than the 12.2% training had added.
Which measure improved most with resistance training?
Upper-body muscle endurance, up 35.4%, followed by lower-body endurance at 24.6%, agility and dynamic balance at 12.2% and gait speed at 8.2%.
Did grip strength and flexibility improve?
No. Handgrip strength (p=.860) and flexibility (p=.683) showed no significant change, separating what the program targeted from what it did not.
Does adding interval training reduce detraining losses?
It pointed that way in this study. After the resistance-plus-interval phase, the second 100-day layoff produced markedly attenuated losses and minimal overall change.
Do these numbers apply to younger lifters?
Not directly. The participants were 16 women aged 60 and over, and the outcomes were functional tests such as agility, muscle endurance and gait speed rather than 1RM.
Source: PubMed