Table 2. Results for strength and power (Frel; Prel) for the Leg Press (LP), Leg Curl (LC), Abdominal Press (AP) and Back Extension (BE) for both groups at 1 week before intervention (pre-test), 1 week after intervention (post-test), and 3 weeks after intervention (re-test). Data are means (±SD). Parameter Group pre-test post-test re-test Cohen’s d (pre-post) Cohen’s d (pre-re) LP Frel (N·kg-1) S+E 50.4 (3.3) 63.3 (13.6) * 64.8 (8.8) * 1.30 2.16 S 48.1 (11.1) 57.8 (16.6) * 61.8 (20.6) * .69 .83 Prel (W·kg-1) S+E 21.1 (3.6) 22.3 (3.7) 23.1 (4.5) * .35 .50 S 19.6 (4.7) 19.5 (4.6) 21.0 (4.5) * .02 .31 LC Frel (N·kg-1) S+E 18.0 (1.5) 19.0 (1.5) 19.5 (1.5) * †  .69 1.05 S 15.7 (3.3) 16.5 (2.5) 15.8 (2.3) †  .27 .04 Prel (W·kg-1) S+E 9.8 (1.1) 10.9 (1.5) * 10.5 (1.3) .85 .50 S 9.1 (2.0) 9.1 (1.7) 9.3 (2.1) .01 .14 AP Frel (N·kg-1) S+E 12.6 (1.4) 12.2 (1.4) 12.5 (1.1) .25 .06 S 11.9 (1.8) 11.6 (1.6) 12.1 (1.1) .17 .11 BE Frel (N·kg-1) S+E 18.4 (4.8) 21.3 (4.8) * 22.4 (5.0) * .59 .81 S 18.7 (6.0) 20.2 (6.1) * 20.4 (5.1) * .26 .31 * indicates significant differences to pre †  indicates significant differences between groups (p < 0.05). Groups: S (strength); S+E (strength + EMS).