Muscle fiber necrosis associated with human marathon runners

Metabolic Consequences of Exercise-Induced Muscle Damage

“…Damage is also visible in the mitochondria and the sarcoplasmic reticulum [17,20] . This initial disruption is followed by degeneration during which the damaged myofibrillar proteins are acted on by proteases.…”

“…This initial disruption is followed by degeneration during which the damaged myofibrillar proteins are acted on by proteases. A number of studies have reported the infiltration of immune cells within 2 to 3 days following injury [14,17] , but other researchers have failed to show an immune response [2,10,20] . Regeneration follows with satellite cells becoming centrally located and replacing the damaged myofibrils.…”

“…These include bench stepping [15] , drop jumps [9,11] and downhill running protocols [8'16] . Other research has examined EIMD following exhaustive exercise containing a large number of SSC contractions, such as marathon running [3,5,10,[17][18][19][20] .…”

Age-related decrements in cycling and running performance

“…20 A large body of work has shown that eccentric activity causes muscle damage, and that this muscle damage is found after marathon and ultramarathon running. 4,11,15,22,25 In contrast, no studies have shown similar pathology in cyclists after endurance cycling events. Therefore, it is reasonable to speculate that the decrements in age-related running times may have been caused by chronic muscle or musculoskeletal damage and perhaps 'premature aging' of the lower limb muscles of older runners, due to the cumulative effects of years of biomechanical stress and eccentric activity related to running training and racing.…”

“…5,13 Several studies have shown that muscle damage occurs after marathon and ultramarathon races. Hidika et al 11 showed that severe muscle damage with signs of fibre necrosis and inflammation occurred in muscle biopsies performed on runners after running a marathon race. In a similar study up to 25% of the muscle fibres of runners after a marathon race showed areas of myofibrillar loss.…”