The adults of Trichinella parasites are small worms (12.5 mm in length and 0.025-0.038 mm in width), which live in the mucosa of the small intestine for 15-20 days and then in the striated muscles at the larval stage for years. The infecting stage is the larva (0.6-1.2 mm in length) present in muscles, which, after the ingestion by another host, develops to the adult stage in the small intestine in about 48 hr; male and female worms mate and females produce newborn larvae starting 5-6 days after infection. Newborn larvae, released in the lymphatic vessels by the female, migrate to the blood vessels and reach all body sites of the host. Only newborn larvae, which reach striated muscles, are able to develop to infective larvae. They penetrate the muscle cells and induce the host cell to change into a nurse cell, in which larvae can survive for years, waiting for a new host to ingest the infected muscles. Some Trichinella species induce the formation of a collagen capsule around the larva in the nurse cell (encapsulated species), whereas other species do not induce capsule formation (nonencapsulated species).
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.