I can only train once a week — or once a fortnight — for 3 months. Will I keep what I built?
Once a week, yes; once a fortnight, partly. The same full session every 7 days held leg strength, quadriceps size and aerobic power for 12 weeks; every 14 days, by week 12, about half the size and aerobic-power gains were gone (our arithmetic: −5.9% CSA and −9.0% power from the post-training level), a fifth of the strength gain (−4.4% 1RM). Stopping gave back almost everything. Untrained young women 12 weeks into training.
Mpampoulis et al. trained 27 untrained young women twice a week for 12 weeks (leg press 4 × 6 at 80-85% 1RM, then 10 × 60 s cycling at 100% of maximal aerobic power), with 7 controls. Leg-press 1RM rose 28.7%, quadriceps cross-sectional area (CSA) 13.1% and maximal aerobic power 20.4%.
The trainees then kept the same session, at the same load, once every 7 days (G7, n = 10), once every 14 days (G14, n = 10), or stopped (GD, n = 7) for 12 weeks, and then everyone stopped for 12 more weeks. Over the reduced period G7 lost nothing measurable.
G14 kept 1RM for 6 weeks (−1.4%, not significant), then lost a further 2.9%; by week 12 it had lost 4.4% of 1RM, 5.9% of quadriceps CSA and 9.0% of maximal aerobic power from its post-training level. GD lost 9.1% of 1RM in 6 weeks and returned to baseline in quadriceps CSA and aerobic power by week 12.
In the final 12 weeks off, G7 and G14 also fell back to baseline (1RM stayed slightly above). The authors summarise once a fortnight as preserving "90 to 95%" of the adaptations; that is 90-95% of the post-training value, not of the gain (see Limitations).
Protocol
Participants: 34 healthy women, 20.03 ± 2.1 y, 60.9 ± 5.6 kg, physical-education students with no systematic resistance or aerobic training for at least 2 years; a priori power analysis asked for 30.
T1-T2 (12 weeks): training group (n = 27) vs control (n = 7), randomly allocated, balanced on body composition, strength and aerobic capacity. Two sessions a week, at least 72 h apart, ~1 h: warm-up, leg press 4 × 6 at 80-85% 1RM (3 min rest, +2.5-5% a week), then 10 × 60 s on a cycle ergometer at 100% of maximal aerobic power at 50 rpm with 60 s passive rest (+2.5-5% each session).
T2-T4 (12 weeks reduced): G7 one session every 7 days (n = 10), G14 one every 14 days (n = 10), GD no training (n = 7); allocation on post-training values (no differences); G7 and G14 kept the intensity and volume of the last regular session.
T4-T5 (12 weeks): complete cessation for all.
Measures (T1, T2, T4, T5; 1RM also at T3 = 6 weeks): DXA body composition; ultrasound quadriceps CSA (all four heads) and vastus lateralis architecture; countermovement jump; leg-press 1RM; maximal aerobic power and heart rate at 100 and 125 W on a YMCA-style cycle test.
Key Results
| Outcome | T1→T2 (training group) | G7, T2→T4 | G14, T2→T4 | GD, T2→T4 |
|---|---|---|---|---|
| Leg-press 1RM | +28.7 ± 10.7% | −0.4% to 6 wk, −0.5% more to 12 wk (ns) | −1.4% to 6 wk (p = 0.056), then −2.9% (p = 0.009); −4.4 ± 3.5% overall | −9.1% to 6 wk, then −6.8% |
| 1RM, kg (T2 / T3 / T4 / T5) | 237.9 → 302.9 | 314 / 312.5 / 310.5 / 257 | 308 / 303 / 293 / 246 | 280.4 / 254.2 / 237.1 / 215 |
| Quadriceps CSA | +13.1 ± 4.7% | −0.6 ± 0.6% (ns) | −5.9 ± 1.8% | −7.6 ± 3.4%, back to baseline |
| Quadriceps CSA, cm² (T2 / T4 / T5) | 44.7 → 50.5 | 49.9 / 49.6 / 43.8 | 53.8 / 50.7 / 47.1 | 46.6 / 43.3 / 42.8 |
| Maximal aerobic power | +20.4 ± 10.3% | −1.4 ± 4.5% (ns) | −9.0 ± 7.8% | −15.8 ± 7.3%, back to baseline |
| Maximal aerobic power, W (T2 / T4 / T5) | 124.5 → 148.0 | 147.5 / 145.2 / 125.3 | 157.5 / 142.5 / 127.5 | 135.7 / 114.2 / 107.5 |
| Heart rate at 100 W | −10.1 ± 6.9% | +3.5% (ns) | +12.2 ± 15.8% | +9.7 ± 2.9% |
| Lower-limb lean mass | +5.0 ± 2.7% | −0.3% (ns) | −1.76% | −1.85% |
| Countermovement jump | no change | no change | no change | no change |
Final 12 weeks off (T4→T5): 1RM −17.4% (G7), −16.5% (G14), −9.3% (GD), all "reaching the pretraining values" (the authors note 1RM stayed slightly above baseline); quadriceps CSA −11.5% (G7) and −6.7% (G14); aerobic power −14.5% (G7) and −10.3% (G14), both to baseline.
Session RPE rose during the reduced period (8.2 ± 0.8 at T2 vs 9.1 ± 0.6 at T4) at unchanged load. Controls changed in nothing.
Mechanisms
Measured: the same session every 7 days kept quadriceps CSA, vastus lateralis thickness and fascicle angle at post-training values; every 14 days all three fell (CSA −5.9%, thickness −5.2%, angle −7.51%), less than stopping.
Measured: in G14, 1RM held for 6 weeks (−1.4%, p = 0.056) and fell by 12 weeks; size was measured only at 12 weeks, so whether strength or size went first is unknown.
Authors' interpretation: intensity maintains strength through neuromuscular factors, volume maintains size; keeping the session's intensity and volume is why once a week preserved everything.
Measured: the same session felt harder by the end of the reduced period (RPE 8.2 → 9.1).
Inference: maintenance only holds while it continues — G7, which lost nothing during the reduced period, lost most in the 12 weeks off afterwards and ended at baseline like everyone else; no reserve was banked.
Practical Application
I can only train once a week — or once a fortnight — for 3 months. Will I keep what I built? Once a week, yes; once a fortnight, partly.The same full session every 7 days held leg strength, quadriceps size and aerobic power for 12 weeks; every 14 days, by week 12, about half the size and aerobic-power gains were gone (our arithmetic: −5.9% CSA and −9.0% power from the post-training level), a fifth of the strength gain (−4.4% 1RM). Stopping gave back almost everything.Untrained young women 12 weeks into training.
A maintenance block delays the loss; it does not store anything. Twelve weeks off after the reduced period took every group back to about baseline, so plan maintenance across the whole busy period rather than front-loading it.
Not from this paper: trained athletes. These were women 12 weeks into their first structured training; gains this new are also the easiest to lose, and an athlete's maintenance floor may be higher (REF-587 notes the athlete gap).
Limitations
Population: untrained young women in their first 12 weeks of structured training (Tier 0-1); neither athletes nor men; adaptations this recent may be lost faster than long-held ones.
Small groups: n = 10, 10 and 7 in the reduced-frequency period, 7 controls; the 1RM loss in G14 at 6 weeks sat at p = 0.056.
Allocation: the first split is described as random (balanced on baseline values); the second was by matched post-training values with no stated randomisation; no assessor blinding is reported.
The headline percentage is easy to misread. "Maintaining 95.6 ± 3.5%, 94.1 ± 1.8%, and 91.0 ± 7.8% of the initial training adaptations" equals 100% minus the loss from the post-training value; against the gain (group means: 1RM +28.7%, quadriceps CSA +13.1%, aerobic power +20.4%), G14's losses are about a fifth of the strength gain and about half of the size and aerobic-power gains (our arithmetic, using whole-group gains because subgroup baselines are not reported).
Narrow outcomes: lower-limb only; no VO2max (aerobic power from an incremental YMCA-style cycle-ergometer test with 3-min stages), no biopsies or EMG; the discussion's "every 14 weeks" is a typo for days.
Funding: none; no conflicts declared.
How this entry was checked and changed
Why this level
n = 34 in all; parallel groups of 10, 10 and 7 (plus 7 controls) in the reduced period, well under 20 per arm; allocation to the reduced-frequency groups was matched on post-training values with no stated randomisation; untrained young women, one lab; read from the full text
Full text (checked 2026-10-15)
"Thirty-four healthy, female physical education students (age: 20.03 ± 2.1 years, body mass: 60.9 ± 5.6 kg"; a power analysis asked for "a total of 30 individuals" (full text).
Training: "4 sets of 6 repetitions at 80–85% of 1-RM in leg press with 3 min rest"; "10 sets of 60 s duration on a bicycle ergometer at 100% of their maximal aerobic power"; "2 times per week, with at least 72 h between sessions" (full text).
Groups: "group G7, who trained once per week (n = 10); group G14, who trained once every 14 days (n = 10); and detraining group (GD) with the complete cessation of training (n = 7" (full text).
T1→T2: 1RM "28.7 ± 10.7%", maximal aerobic power "20.4 ± 10.3%", heart rate at 100 W "10.1 ± 6.9%", lower-limb lean mass "5.0 ± 2.7%", quadriceps CSA "13.1 ± 4.7%" (full text).
1RM T2→T3: G7 "−0.4 ± 1%", G14 "−1.4 ± 2%, p = 0.056", GD "−9.1 ± 2.3%"; T3→T4: G14 "−2.9 ± 3.1%; p = 0.009", GD "−6.8 ± 3.2%" (full text).
Table 2 kg: G7 "314 ± 41.4 | 312.5 ± 41.1 | 310.5 ± 40 | 257 ± 43.1"; G14 "308 ± 35.7 | 303 ± 30.9 | 293 ± 27.4"; GD "280.4 ± 26.4 | 254.2 ± 23.5" (full text).
Abstract: G14 "(−4.4 ± 3.5%; −5.9 ± 1.8%; −9.0 ± 7.8%, respectively, p < 0.05), maintaining 95.6 ± 3.5%, 94.1 ± 1.8%, and 91.0 ± 7.8% of the initial training adaptations" (full text).
Aerobic power T2→T4: G7 "−1.4 ± 4.5%", GD "−15.8 ± 7.3%"; heart rate at 100 W G14 "+12.2 ± 15.8%" (full text).
Quadriceps CSA T2→T4: G7 "−0.6 ± 0.6%", G14 "−5.9 ± 1.8%", GD "−7.6 ± 3.4%"; T4→T5 G7 "−11.5 ± 3.2%", G14 "−6.7 ± 2.2%" (full text).
T4→T5 1RM: G7 "−17.4 ± 5.9%", G14 "−16.5 ± 6.8%", GD "−9.3 ± 4.6%"; aerobic power G7 "−14.5 ± 15.3%", G14 "−10.3 ± 11.9%" (full text).
Lower-limb lean mass T2→T4: G7 "−0.3 ± 1.8%", G14 "−1.76 ± 2%", GD "−1.85 ± 3.6%" (full text).
VL thickness and fascicle angle in G14: "−5.2 ± 2.3%" and "−7.51 ± 4%" (full text).
RPE "8.2 ± 0.8 vs. RPE at T4 9.1 ± 0.6" (full text).
"The authors received no external funding"; "there were not any conflicts of interest" (full text).