Take a look at the study (well the ACE press release version), the link is posted at the bottom of the article. To me it seems like a poorly designed study.
Subjects: 6 male / 6 female - all with weight training experience (not bad so far).
Test 1 RM of the following: Squats (90 degrees), vert. leg press, horizontal leg press, step-ups, lunges and four-way hip extension.
1RMs for single leg squats and quadrupled hip extension were not tested since these are body weight.
My comments- not bad so far, but if these were truely 1 RM isn't it likely that the later tested movements could be compromised by previous movements? I also have to assume most, if not all, needed prior sets to determine the 1RM.
Test methodology - Subjects preform a 1RM squat followed by 5 reps of single leg squats, step-ups, lunges and quadrupled hip extension.
Movement order determination was random and 5 reps were at 80% of 1 RM.
Tested remaining movements, however it is unclear if the 5 reps for squats were done or if it refers to the 1RM again.
**My Comments- I like the randonness and the 80% for 5 reps, however it is unclear if the 1RM squat was preformed prior to each movement or only once. My main concern is that I would think a degree of fatique would set in after the first few movements, expecially on Day 3 and for sure if a 1RM squat was done prior to the 5 reps.***
quadrupled hip extension, lunges and step-ups were statistically greater muscle activation than squats.
Others were either statistically less muscle activation than squats or not statistically different.
The one bright point of the press release was the researchers noted that going below 90 degrees in the squat may increase activation. (Not so bright point, they used 90 degrees since going below was an injury risk - who knew (yes that's sarcasm)).
Is it really surprising that an isolation movement activates the muscle more that a compound movement? Unfortunately it ignores the other benefits of compound movements.
Oh well, could we really expect any better from main stream trainers and main stream media.
Last comment. I also found it interesting how the media only mentioned selected easier movements and neglected the additional comments on squats. I guess easy things make people feel good (until they don't get results).