At my gym they have a leg curling machine that slants from the waist down at about a 45 degree angle. You have the ability to adjust the leg curler forwards and backwards to adjust to your size and different levels for how far you want the curler to go down. I position the back of my head under the curler, where the back of my feet should be, and lift upwards. I do ten sets. I then turn on my side and position the curler on the flat portions of my head just behind the ear. I do ten reps and then do the other side. It works perfect. For the front of my neck I just get a flat bench, lay flat on my back so that only my neck hangs over the edge and do neck-sit-ups. I purchased 5lb and 10lb neck weights from Titleboxing to increase strength. http://store.titleboxing.com/necstreb.html
Bridging? Is that where you lie flat on your back then arch up using the top of your head as an anchor along with your feet? I do shrugs but my gym doesn't have a four way neck machine. I guess it's due to liability reasons.
Some people bridge that way, but I believe it's better to go all the way over to your forehead (and nose...and chin...if you can). You can do either front or back bridges, or both: http://www.youtube.com/watch?v=7JwxulF13LA&feature=related
<object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/u8S_6V-5wmY&hl=en"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/u8S_6V-5wmY&hl=en" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object> <object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/-ElBjtSCdX4&hl=en"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/-ElBjtSCdX4&hl=en" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>
