diff --git a/examples/pybullet/gym/pybullet_envs/gym_locomotion_envs.py b/examples/pybullet/gym/pybullet_envs/gym_locomotion_envs.py
index 6220b28cf..93cd8af33 100644
--- a/examples/pybullet/gym/pybullet_envs/gym_locomotion_envs.py
+++ b/examples/pybullet/gym/pybullet_envs/gym_locomotion_envs.py
@@ -39,6 +39,9 @@ class WalkerBaseBulletEnv(MJCFBaseBulletEnv):
 			
 		
 		return r
+	
+	def _isDone(self):
+		return self._alive < 0
 
 	def move_robot(self, init_x, init_y, init_z):
 		"Used by multiplayer stadium to move sideways, to another running lane."
@@ -60,8 +63,8 @@ class WalkerBaseBulletEnv(MJCFBaseBulletEnv):
 
 		state = self.robot.calc_state()  # also calculates self.joints_at_limit
 
-		alive = float(self.robot.alive_bonus(state[0]+self.robot.initial_z, self.robot.body_rpy[1]))   # state[0] is body height above ground, body_rpy[1] is pitch
-		done = alive < 0
+		self._alive = float(self.robot.alive_bonus(state[0]+self.robot.initial_z, self.robot.body_rpy[1]))   # state[0] is body height above ground, body_rpy[1] is pitch
+		done = self._isDone()
 		if not np.isfinite(state).all():
 			print("~INF~", state)
 			done = True
@@ -89,7 +92,7 @@ class WalkerBaseBulletEnv(MJCFBaseBulletEnv):
 		debugmode=0
 		if(debugmode):
 			print("alive=")
-			print(alive)
+			print(self._alive)
 			print("progress")
 			print(progress)
 			print("electricity_cost")
@@ -100,7 +103,7 @@ class WalkerBaseBulletEnv(MJCFBaseBulletEnv):
 			print(feet_collision_cost)
 
 		self.rewards = [
-			alive,
+			self._alive,
 			progress,
 			electricity_cost,
 			joints_at_limit_cost,
@@ -135,6 +138,9 @@ class HalfCheetahBulletEnv(WalkerBaseBulletEnv):
 	def __init__(self):
 		self.robot = HalfCheetah()
 		WalkerBaseBulletEnv.__init__(self, self.robot)
+		
+	def _isDone(self):
+		return False
 
 class AntBulletEnv(WalkerBaseBulletEnv):
 	def __init__(self):
@@ -172,4 +178,3 @@ class HumanoidFlagrunHarderBulletEnv(HumanoidBulletEnv):
 		s = HumanoidBulletEnv.create_single_player_scene(self, bullet_client)
 		s.zero_at_running_strip_start_line = False
 		return s
-