Try rucking as low-impact cross-training
Added
Rucking is walking with a weighted pack. A Cleveland Clinic sports medicine doctor suggests starting light, sometimes with an empty pack, then raising only one thing (weight, distance, or time) by about 10% a week. A real rucksack holds weight higher and steadier than a loose backpack.
The result
Result: Cleveland Clinic: rucking can burn up to three times the calories of walking without a pack; its example starting load is about 5 lb.
Note: Not medical advice. Talk to your doctor before changing your training, diet, or supplements.
Source
Cleveland Clinic (opens the original source in a new tab). Check it for the latest numbers before you act.