There is popular belief that strength training for runners should be high rep, low load (weight or resistance) to mimic the endurance demands of running. This is incorrect.
Heavy strength training completed 2-3 times per week (for 6 weeks or more) can improve endurance running performance economy and maximal sprint speed.
Greater performance benefits are reported with heavy and explosive strength training compared to strength endurance training.
The amount of force that goes through your joints multiplies from standing (1x), walking (4x) to running (8x) which means that the amount of force required of your muscles will also multiply, especially over longer distances or higher intensities. Adding weights or heavy resistance stimulates tissue adaptations (e.g. stronger bones, muscles and resilient tendons) so that your body can withstand the physical stress (e.g. endurance running).
While these adaptations occur as you progressively build your running distance, strength training is protective against joint-related or muscle-related injuries to limit shearing forces that harm your joints with plyometric and impact training.
All too often we find that strength training is the first to be sacrificed by runners - especially when upping the mileage as they train for their next race. The benefits of strength training are greater with consistency and over the long term, and should be prioritised as part of a training regime to maximise running economy and minimise injury risk.
Speak to your physiotherapist about commencing a strength program to help you become a better runner!