Older man on a leg press machine talking with a coach in a gym

Heavy Strength Training at Retirement Age: Lessons From a 4-Year Trial

9 min read

Muscle strength and size decline with age. Strength training slows that loss, but most trials run for months and stop. Few follow people for years afterwards to see what lasts.

A Danish trial called LISA did. It gave adults at retirement age one year of heavy strength training, moderate training or no training, then tested them again two and four years after the start.

451
Adults at retirement age randomised into three groups
Bloch-Ibenfeldt et al. 2024, LISA trial, Denmark
3 a week
Supervised heavy sessions for one year, at about 70 to 85% of one-rep max
Bloch-Ibenfeldt et al. 2024, BMJ Open Sport and Exercise Medicine
151.5 Nm
Leg strength in the heavy group at four years, against 149.7 Nm at the start
Bloch-Ibenfeldt et al. 2024, isometric knee extension
369
People who came back for testing at four years
Bloch-Ibenfeldt et al. 2024, mean age 71
Source: Bloch-Ibenfeldt et al. 2024, BMJ Open Sport and Exercise Medicine. Nm (newton metres) measures turning force at the knee. One-rep max is the most weight you can lift once with good form.

How the LISA trial worked

LISA stands for LIve active Successful Ageing. Researchers at the Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, randomly assigned 451 adults at retirement age to one of three groups for one year. None had done structured resistance training before. The group sizes were 149 for heavy training, 154 for moderate training and 148 for a control group.

The control group did no set training. The researchers encouraged them to keep up their usual activity and invited them to regular cultural and social events. Participants were tested at the start, after the training year, and again two and four years after the start. Mads Bloch-Ibenfeldt and colleagues published the four-year results in 2024 in BMJ Open Sport and Exercise Medicine.

Heavy training
  • Three supervised sessions a week at a commercial gym
  • Machine-based, full-body, nine exercises
  • 3 sets of 6 to 12 repetitions at about 70 to 85% of one-rep max
  • 6 to 8 weeks of build-up before the heavy loads
Moderate training
  • One session a week at the hospital, two at home
  • Circuit training with body weight and resistance bands
  • 3 sets of 10 to 18 repetitions at about 50 to 60% of one-rep max
  • The same nine movement patterns as the heavy group

The trial did not test one-rep max directly. It estimated it from the number of reps people managed with a given weight, using a standard formula.

Leg strength four years on

At four years, 369 people came back for testing: 128 from the heavy group, 126 from the moderate group and 115 from the control group. Their mean age was 71, with a range of 64 to 75, and 61% were women. The headline measure here is leg strength: the maximum turning force the thigh muscles produce at the knee while pushing against a fixed pad, measured in newton metres.

The heavy group's leg strength was 149.7 Nm at the start and 151.5 Nm at four years, so it held at its starting level three years after training ended. The control group fell from 144.4 to 134.5 Nm, a drop too large to put down to chance. The moderate group fell from 147.6 to 142.9 Nm. That drop did not reach statistical significance in the main analysis, but it did in a separate comparison of start and four-year values.

Leg strength at the start and four years later Leg strength, Nm. Dark dot = start, light dot = 4 years 130 140 150 160 Heavy training 149.7 to 151.5 Moderate training 147.6 to 142.9 Control group 144.4 to 134.5
Source: Bloch-Ibenfeldt et al. 2024, BMJ Open Sport and Exercise Medicine. Group means at baseline and four years after the start. Training lasted one year. The axis starts at 130 Nm to show the changes.

Over the four years, the change in the heavy group differed significantly from the changes in both other groups. The authors found it somewhat surprising that moderate training showed no lasting effect on muscle at four years, since it had improved lean mass and function during the training year, though less than heavy training.

What held up, and what did not

Total lean body mass, which includes muscle, held steady in the heavy group, at 47.5 kg at the start and 47.3 kg at four years. It fell slightly in the moderate and control groups. The authors described these differences as minor. Visceral fat, the fat stored around the organs, stayed level in both training groups and rose in the control group.

Other measures fell in every group with no difference between them: leg power, which was the trial's primary outcome, handgrip strength, and leg lean mass. Leg power is how quickly your leg muscles produce force, rather than the maximum force. So one year of heavy lifting preserved leg strength, but it did not stop all age-related decline.

Why heavy loads might last longer

The heavy group kept its leg strength even though its leg lean mass went down. The authors suggested changes in the nervous system, which controls how muscles are recruited, might play a role. The trial did not measure these changes directly.

The two-year LISA report found strength was maintained 12 months after the heavy training year, but not after moderate training. The authors proposed that higher loads may play an important role in producing long-lasting adaptations. The heavy and moderate programmes also differed in setting, equipment and supervision, so a single trial cannot single out load. The trial is continuing, with 7-year and 10-year follow-ups planned.

Who these results apply to

The authors described their participants as well-functioning older adults. At the start they averaged about 9,500 steps a day, and the authors judged the group likely healthier and more active than the average ageing population. Even so, about 80% had at least one chronic medical condition. Of the 82 people who dropped out, most left because of lack of motivation or severe illness, and dropouts had a higher body mass index at the start. Results in frailer or less active people could differ.

How to apply it

The NHS advises adults aged 65 and over to do activities that improve strength, balance and flexibility on at least 2 days a week. It says to do strength exercises until you need a short rest before repeating them. A 2022 paper in Age and Ageing by Christopher Hurst and colleagues proposed a programme for sarcopenia, the age-related loss of muscle strength and mass: two sessions a week, upper- and lower-body exercises, 1 to 3 sets of 6 to 12 reps, with a relatively high degree of effort.

The NHS advises you speak to a GP first if you have not exercised for some time, or if you have medical conditions or concerns. About 80% of LISA participants had at least one chronic condition, so this step matters. The steps below are our coaching suggestion, built on the LISA heavy programme and these guidelines.

  • Build up first. LISA used 6 to 8 weeks of build-up before heavy loads. Use that time to learn each machine and movement with light weights.
  • Train two or three times a week. Two sessions meet the NHS guideline. LISA used three.
  • Cover the whole body. Include a leg press or squat, a chest press, a seated row and a hip hinge such as a deadlift, using machines if you are new to lifting.
  • Work in the 6 to 12 rep range with real effort. Pick a weight where the last reps of each set are hard while your form stays clean. When you can do 12 clean reps on every set, add the smallest step available.
  • Get supervision at the start. The LISA heavy programme was supervised. A qualified coach helps you set loads and technique safely.

Common mistakes

  • Staying with only moderate loads for good. In LISA, the moderate programme did not hold leg strength at four years the way heavy training did.
  • Jumping straight to heavy loads. The trial built up over 6 to 8 weeks first.
  • Treating one year as a full fix. Leg power, grip strength and leg lean mass still fell in every group over four years.
  • Skipping balance work. The NHS groups strength, balance and flexibility together for adults aged 65 and over.

Frequently asked questions

How long do strength gains last after you stop training?
In the LISA trial, adults who did one year of heavy training kept their leg strength at its starting level four years after the start, three years after training ended. The control group lost strength over the same period.
What counts as heavy?
LISA used about 70 to 85% of one-rep max for 3 sets of 6 to 12 reps. In practice, the last reps of each set should be hard while your form holds.
Is it too late to start at retirement age?
LISA participants were around retirement age, aged 64 to 75 with a mean of 71, and none had done structured resistance training before. Those in the heavy group still kept their leg strength four years on.
Do I need a gym?
The LISA heavy programme used machines at a commercial gym. The moderate programme, mostly at home with bands, did not preserve leg strength as well. It also differed in setting and supervision, so the trial cannot say which factor mattered. The authors think heavier loads may be part of the reason.
Should I keep training after the first year?
LISA tested what remained after training stopped. It did not test continued training. The NHS advises activities that improve strength, balance and flexibility on at least 2 days a week for adults aged 65 and over.

The bottom line

In the LISA trial, one supervised year of heavy, machine-based strength training at retirement age kept leg strength at its starting level four years later, while the control group lost strength. Moderate band-based training did not match it. Lean mass held better with heavy training and visceral fat stayed level in both training groups, but leg power, grip strength and leg lean mass fell in every group. The participants were healthier than average, so results in frailer people could differ. If you are near retirement, a gradual build-up to heavy, supervised training two or three times a week is a sensible place to start, based on this trial and NHS guidance.

Start heavy training with a coach
DT Fitness London builds supervised strength plans for older adults, starting with a build-up phase and progressing loads safely.
Book a consultation at dtfitnesslondon.com

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