In any case, there are no significant differences between this variant and the basic machine bench press. (bodybuilding-wizard.com)
McCaw & Friday (1994) also compared the free - weight and smith machine bench press at 60 and 80 % of 1RM and found no difference in triceps brachii muscle activity at equivalent loads. (strengthandconditioningresearch.com)
Scientists from the California State University at Long Beach examined the amount of muscle activation that occurs when performing a barbell bench press versus a Smith machine bench press. (ironmanmagazine.com)