Pig selection companies aim to improve simultaneously carcass morphology, especially muscularity, defined as muscle thickness relative to skeleton dimensions (Purchas, 1991), and meat leanness. It is likely that postmortem metabolism and muscle morphology are related. Post-mortem metabolism is strongly influenced by metabolism during the pre-slaughter period (Lawrie, 1966). During this period, muscle morphology, which influences the way muscles are used, probably affects post-mortem metabolism and consequently technological meat qualities. Improvement of muscularity may influence post-mortem metabolism in relation to changes in contractile and metabolic fibre type (Klont et al. 1998, Laville et al., 2002). As alternative pork production (outdoor production, different genetic types) gains an increasingly important place on the market, it is further relevant to evaluate effects of rearing environment and genetic background on carcass composition and meat quality. This study is part of a larger study.