Hi Glenda – This was one of my favourite hobby horses when working for the DHB’s –
See Grandjean (Fitting the task to the person – 5th ed) Table on forces for pushing and pulling p 140 (this is 1991 n could have been surpassed) – and you can hire a metre to demonstrate – we never got round to it but would love to hear if you do. There is info on initiation force and sustained force. NB cornering for beds – it is rarely in a single direction
Regarding the maximum recommended load for one staff person to push a load
HSE (Health and Safety Executive) website has information and a risk assessment tool on pushing and pulling that you may find helpful.
Hope this helps