Quote[/b] (9to5lifter @ Jan. 10 2006,9:59)]You can perform negatives with some exercises even if you train alone. For example, chins or dips, helping the concentric portion with your feet. With other exercises you can lift the weight using both arms (or legs) and then lower it with one.
If the above is not an option, you could go on with your 3RM. If you want to, cluster your sets to reach a predetermined number of total reps.
Whatever you decide, throw in some metabolic work too (if you aren't doing this already).
Best of luck,
Dimitris