To the best of my knowledge, this phrase is credited to the cross country coach and team of Pope John High School of Sparta, New Jersey. It is used primarily during the summer training season.
Here's how it works: running, especially during the summer season when heat indices top 100 degrees Fahrenheit regularly, can become monotonous and bore some. For both the elite, competitive, and casual runner, this presents some small problems, mainly a desire to not run; this is a bad thing. In order to keep the desire to run alive and kicking all-throughout the summer swelter, runners can turn to various mid-run amusements. Some examples would be trail hiking/running, river running (removal of sneakers strongly suggested), and of course The Grip of Death.
The proper usage of The Grip is in the midst of a group of runners that you know better than as acquaintances. If the pace is lacking, or the conversation dull, then you have stumbled across your opportunity! Scan the road ahead for any non-motorized traveler moving in the same direction as you. A squirrel or other small mammal may be substituted in a pinch. Once a target has been acquired, you must move directly into the activation stage.
The activation stage must proceed as thus. First, the caller of The Grip must make a tight fist and raise it up into the air, and look at all the other runners in the group to get their attention. Secondly, the caller yells out in one short breath "Grip of Death" in a slightly strained voice as if one were constipated. Lastly, the caller issues the challenge, to which all within the auditory limit of pride must respond. The challenge is thus:
"See this? This is the grip.
Once you get inside there,
There ain't no getting out."
The challenge may be emphasized by pointing to the fist during line two and shaking the head in a negative matter during the final line.
Upon completion of the challenge, all fellow runners within the auditory limit of pride as to be defined by the caller (which is to ensure that the group can repeatedly mock any who do not respond) start to run faster. The trick is you need to continually accelerate and run faster and faster until you catch your target. Once you have caught up with the targeted runner, you have satisfied the requirements of The Grip. The only remaining catch is that once The Grip is called and executed, the target may not pass you back.
The best targets for The Grip are runners of extreme age (both young and old), bicyclists attempting to go uphill (watch out for upcoming downhills...), and most importantly attractive members of the opposite sex. Shirtless members who fall into the last category are a no-brainer. All in all, The Grip adds a new element of play and entertainment to a long summer of running and is always fun to implement around friends.