Beginners Guide to riding Fixed/Single Speed in London

My bike rucksack (MTN bike bag) cleverly has the connecting strap (the one that connects the shoulder straps) lower than usual (just under the ribs), to allow arm movement when cycling.

If a backpack for cycling is only going to have one sternum strap then higher is better. This means that when you lean forward on the bike and your arms and shoulders move inwards, it's the sternum strap keeping the main straps away from your shoulder joint/arms rather than your shoulder joint/arms themselves stopping the straps sliding off.

But every bagmaker has their own theory on design...so long as you're happy and comfortable, that's good enough for me. ;)