Will a 1-2 week vacation from the gym make you stronger?

Short answer

No. Taking 2 full weeks off did not raise strength; bench press and squat dropped by less than 2%. Strength went up only with short breaks of 2-7 days, like right before a competition.

Will a 1-2 week vacation from the gym make you stronger?
'Full rest → fatigue gone → more strength' — does this formula hold?
People say the weights feel lighter after a good break. We checked whether strength goes up, stays the same or drops, depending on how long you rest.
A few days off sometimes raised strength
Most gains came from breaks of 7 days or less
A review of studies found that most improvements came with 7 days of rest or less. The squat rose 1.7-4.9% (2.0-5.5 kg) and the bench press 1.4-4.9% (1.3-5.5 kg). Researchers credited the recovery from built-up fatigue.
But even 2 days and 4 days differed
After 4 days off, the bench press dropped
At the end of 6 weeks of training, 12 people cut their training for 1 week, then rested 2 or 4 days. The 2-day group improved their bench press and three-lift total. The 4-day group improved their deadlift, but their bench press dropped.
What about 2 full weeks off?
Strength did not rise; it slipped a little
12 people stopped training for 14 days. Bench press fell 1.7% and squat 0.9%, and neither change was meaningful. But strength while lowering a weight under control fell in every person, by 12% on average, and the fast fibers that produce explosive force got 6.4% thinner.
Hormones went up, strength did not
Testosterone rose 19.2% during the break
Over the same 14 days, testosterone rose 19.2%, growth hormone rose 58.3% and the stress hormone cortisol fell 21.5%. The body was in a better state for building muscle. Strength still did not rise. The researchers concluded that without a training stimulus, these changes do not reach the muscle.
A 1-week break mid-program shrank the gains
The group that took 1 week off in 9 added 3.4 kg less to their squat
39 people trained for 9 weeks, and one group took a full week off halfway through. Their best squat rose 13.0 kg, versus 16.4 kg in the group that kept training. Thigh muscle thickness grew about the same in both groups.
The longer the break, the bigger the loss
An analysis pooling 103 studies
An analysis pooling 103 studies of stopping training found that strength fell more the longer people rested. A later review of this analysis noted that the rate of loss is similar up to 2 weeks, then speeds up from day 15.
Bottom line: a vacation will not make you stronger
But for up to 2 weeks, your max lifts drop less than 2%
The rest that raised strength was 2-7 days, like right before a meet. Taking 1-2 full weeks off did not raise strength, but the drop in bench press and squat stayed under 2%. You can enjoy your vacation with peace of mind; just drop the hope that rest alone will make you stronger.