I always think it is best to be prepared and save the time and energy of local rescue teams to urgent and serious rescues. I believe with the right thought and packing the right essentials, you can avoid straining local rescue groups resources.
Whether trail running or hiking in the front or back country, it's always an idea to be well prepared as things can go and do go wrong no matter how well you plan. If you are not sure what front and back country is, then that's fine as I will explain this.
Basically front country trails tend to be well used and close to areas of population and are well signed. Back country trails tend to be some distance from areas of population; trails are less used and usually no signs and the trail is found by following the trails markers.
Sometimes it's not always easy to find a partner or a group to run with and I have done some longer trail runs on my own due to time constraints etc. But if you can, I would always recommend to go with another runner or hiker or a group. This is because if one of you gets injured then the other person or persons can raise the alarm if required or help you get back off the trail.
Back to the ten essentials and there is some debate on what you should take and the list has been updated through the years. I tend to stick with what is recommended by our local search and rescue teams here in BC.
The ten essentials:
1. Light - no mater how early in the day you set off, weather and trail conditions can change so a head lamp or a flashlight with extra batteries can come in very handy. Even if you set off early but become injured, then it may take time for help to arrive and a light will help with your navigation and to signal help.
2. Signalling device - this would be a good quality whistle, bear banger or a pencil flare. These methods save time and energy that could be used to sustain yourself until help arrives.
3. Fire starter - waterproof matches (alternatively normal matches kept in a waterproof bag) or a lighter. Another option is a commerical fire starter from a local outdoor/camping store or a camping candle. Keeping warm or signalling for help can be essential, especially if up high in the mountains or in the back country or if the weather turns.
4. Extra clothes - hat, gloves, fleece jacket and/or gortex jacket, gortex pants (trousers to those outside of North America), thermal underwear, hiking or thick socks. Not all of these may be to hand or needed depending on the weather and temperature, so the key is to pack extra layers (layering is keep to keep in heat) and a spare top for example to get out of your sweaty shirt.
5. Pocketknife - a decent bladed pocketknife or a small pocket multi tool. This can be used to cut brush and small branches for shelter and for a fire.
6. Shelter - an orange bivy/plastic sack that can be used as a sleeping sack and will attract attention from above if a helicopter rescue is required or makes it easier to be spotted by light aircraft. A thermal tarp or a foil blanket would also help to keep in the heat and to use for signalling.
7. Water & food - Extra water is always an idea to bring along in case you are out longer than planned or you have to stop and wait for help. It's maybe an idea to carry a life straw or similar water filter so that you make use of natural water courses. High energy food is ideal such as energy bars to keep you going if your trip gets extended.
8. First aid kit - a small first aid kit should be sufficient and should include a small splint, dressings, blister dressings, protective gloves and a face mask.
9. Navigation - A map and compass would be the most basic and necessary items to carry ( I'd also recommend searching for local orientation group and heading along classes to brush up on your map and compass skills). Also a GPS device or if in the front country a cell phone with GPS inbuilt.
10. Communication - a cell phone turned off to save battery and in a water proof bag for a sos call. If you do a lot of back country trails, then it might be worth investing in a two way communicator like the spot or inreach devices (these devices can be quite a layout, monthly cost and then a per use cost, but would be worth the money if you come into difficulty).
Always plan your route and let someone responsible know your route and rough time of when you should finish your route. Another idea is to leave a note in your car if you're parking near the trail head or if the local rangers hut has route plan sheet then leave your details on that.
Make sure to wear the appropriate footwear and clothing for the route, weather and temperatures. If things get difficult regards the route or terrain you can always turn back and try the route another time. Its always better to come back in one piece.
Have fun with your runs and hikes and stay safe.