I would start with a risk assessment of the tasks that employees do that cause strains to help identify where you might be able to engineer tooling to alleviate the manual aspect of the task. I have worked with teams who incorporate stretching into their pre-shift meetings to help with strain/MSD concerns. In some jobs it might not be feasible to engineer solutions to help with strains, in this case, continuous reminders of situational awareness is important.

We have our front line employees perform stretch and flex excercises before commencing work, once in the field it is mandatory that any item over 50lbs in mass weight requires two people to lift it. Furthermore if the item is too long, bulky or has akward dimensions it will require two people (more If needed) regardless if it exceeds the 50lb rule.

Hope this works.

One item to look at if employees are task with numerous lifting tasks. Is there a possibility to use carts and other lifting devices to assist in those tasks?

I suggest implementing an ergonomic task force. You can identify your high-risk areas based on the previous injuries and then expand from there. Use the Plan, Do, Check, Act (PDCA) approach to determine the best solution for that process or task, get employee(s) feedback and input before implementing, work with the employee(s) to implement, re-evaluate to see if the control helped, and continually improve.

Some controls may be engineering controls, like carts, lifts, assisted equipment, work space rearrangement; administrative controls, like training, procedure changes, time/repetition limits, or stretching programs; or PPE, like gloves, better shoes, knee pads, anti-fatigue mats.