A compression-release engine brake system (12, 212) for effectuating a compression-release engine braking operation in connection with an internal combustion engine comprising an engine cylinder, at least one intake valve, at least one exhaust valve and at least one exhaust valve spring exerting a closing force on the at least one exhaust valve to urge the at least one exhaust valve into a closed position, the engine cylinder being associated with a four stroke piston cycle comprising an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke, the compression-release system (12, 212) comprising a lost motion exhaust rocker assembly (16, 216) comprising: an exhaust rocker arm (18, 218, 318); an actuation device including an actuation piston slidably disposed in an actuation bore formed in the exhaust rocker arm (18, 218, 318) and movable between retracted and extended positions, the actuation device configured to be operatively associated with the at least one exhaust valve to permit unseating thereof from the closed position; a reset device (26, 360) including a reset check valve (36, 342) and a slider assembly (32, 332) operatively connected to the reset check valve (36, 342); and a hydraulic fluid circuit within the exhaust rocker arm (18, 218, 318); the actuation bore defining an actuation cavity delimited by the actuation piston within the actuation bore above the actuation piston, the reset check valve (36, 342) disposed in a reset bore (38, 338) formed in the exhaust rocker arm (18, 218, 318), the reset bore (38, 338) being in fluid communication with the actuation cavity through at least one connecting conduit (231, 323) of the hydraulic fluid circuit, the reset check valve (36, 342) operable between an open position and a closed position and biased toward the closed position thereof so that a hydraulic fluid is locked in the actuation cavity when the reset check valve (36, 342) is in the closed position thereof, and flows bi-directionally through the reset check valve (36, 342) when the reset check valve (36, 342) is in the open position; the slider assembly (32, 332) including a slider-piston (48, 348) slidably disposed in the reset bore (38, 338) of the exhaust rocker arm (18, 218, 318), the slider-piston (48, 348) movable relative to the exhaust rocker arm (18, 218, 318) between an extended position and a retracted position, the slider-piston (48, 348) biased toward the extended position, the slider assembly (32, 332) operatively associated with the reset check valve (36, 342) so that in the extended position the reset check valve (36, 342) is free to move toward the closed position, and in the retracted position the reset check valve (36, 342) is movable to the open position thereof by the slider-piston (48, 348). an exhaust rocker arm (18, 218, 318); an actuation device including an actuation piston slidably disposed in an actuation bore formed in the exhaust rocker arm (18, 218, 318) and movable between retracted and extended positions, the actuation device configured to be operatively associated with the at least one exhaust valve to permit unseating thereof from the closed position; a reset device (26, 360) including a reset check valve (36, 342) and a slider assembly (32, 332) operatively connected to the reset check valve (36, 342); and a hydraulic fluid circuit within the exhaust rocker arm (18, 218, 318); the actuation bore defining an actuation cavity delimited by the actuation piston within the actuation bore above the actuation piston, the reset check valve (36, 342) disposed in a reset bore (38, 338) formed in the exhaust rocker arm (18, 218, 318), the reset bore (38, 338) being in fluid communication with the actuation cavity through at least one connecting conduit (231, 323) of the hydraulic fluid circuit, the reset check valve (36, 342) operable between an open position and a closed position and biased toward the closed position thereof so that a hydraulic fluid is locked in the actuation cavity when the reset check valve (36, 342) is in the closed position thereof, and flows bi-directionally through the reset check valve (36, 342) when the reset check valve (36, 342) is in the open position; the slider assembly (32, 332) including a slider-piston (48, 348) slidably disposed in the reset bore (38, 338) of the exhaust rocker arm (18, 218, 318), the slider-piston (48, 348) movable relative to the exhaust rocker arm (18, 218, 318) between an extended position and a retracted position, the slider-piston (48, 348) biased toward the extended position, the slider assembly (32, 332) operatively associated with the reset check valve (36, 342) so that in the extended position the reset check valve (36, 342) is free to move toward the closed position, and in the retracted position the reset check valve (36, 342) is movable to the open position thereof by the slider-piston (48, 348).