Oprah's 'summer favorite' helps back-pain sufferers, too
                                
                                
                                    (Newser) -
                                    FitFlops, the sandals that exercise your leg and derriere muscles as you walk, are this summer’s must-have, Newhouse News Service reports. With celebrity support from Heidi Klum to Jennifer Garner, the fitness flip flop made Oprah’s “summer favorites” list, and has sold a million pairs since launching...