It seems a good strategy with a 401K to invest using AAII guidance, or their tool SiPro. For example, looking at link Performance History | AAII: The American Association of Individual Investors
it seems like several methods outperform the indexes, e.g.,
Graham Enterprising Investor, Revised,
Piotroski Hi-F Score,
O'Shaughnessy Tiny Titans
O'Neill's CAN SLEM
Est Rev: Up 5%
Additionally, SiPro can be used at any time to get the candidates. Some additional screens developed at Keelix.com, momentum screens, appear to perform even better for 4 week holds, picking a list of screens and only the top few.