I have always thought that the least number of tools and technology stuff I carry, the better it is. Besides, since I think that differently than other sports you do not need much for running, I have a rather essential and pragmatic approach on running and things I need in general. The following tools are extremely simple things that might be unknown for you, which could improve your training experience and daily life, with low expenses and not much of a time effort.
- Massage stick: very useful for recovering legs and strengthening muscles
- Roller: beneficial for legs, muscles and back problem, can be use almost the same way as a massage stick
- Gym ball: useful especially for your spine and balance
- Balance ball: useful for your ankles, knees, balance and legs side muscles (i.e. the ones you never train!)
- Empty bottle: if used by rolling your feet on it, could be really good for relaxing and proprioception exercising