Post pregnancy training can be done once the new mum has had her 6 week check-up (this would be longer for C section - anything up to 3 months).
It is important for new mums to feel like they are getting something out of their training but definitely not be overtraining or working to maximum fatigue. Like with ante-natal training, listening to the body is a must. If you have had broken sleep and feel like training is not an option, opt for a gentle walk instead as this can help to reduce cortisol levels in the body and is great to unwind the mind.
One of the main concerns for the new mum is “getting the jeans back on” or flattening the jelly belly effect that giving birth tends to have. Starting some really basic core exercises on the floor can really help to start tightening the muscles before embarking on more intense advanced exercises. Like with any exercise it is most important to feel the correct muscles working, rather than trying to squeeze as many repetitions and sets out as you can, especially if limited for time. So pick three exercises and do your reps slowly, with control. Make sure exercises are completed with as much range of movement as possible and take adequate rests in between sets to aid recovery.
If energy levels are good, an all over body circuit would be my best recommendation, as fitting everything into your new baby routine can be extremely challenging. Completing a body weight home programme that works all major muscle groups such a legs, back, chest and shoulders will help to build muscle and decrease body fat.
If new mums are breast feeding they must keep calories up, so getting the balance between training and nutrition is really important. Workout, but not until your flat out, would be my best advice!