In my experience, bicarb will help for sure. Take 0.3g/kg of bodyweight about 60-90 mins before you run. So 70kg bw take 21g, which equals 4 teaspoons essentially (as a teaspoon is about 5g). Take it with powerade or something because it tastes like shit. It shouldnt be a prob if you take it as 0.3g/kg bodyweight but try it in training before hand if you have the chance.
Other option is caffeine, take 200mg (we use 2x100mg no doze tabs) 45 mins before hand and it will help too. Use them both if you are really desperate.