Exercise machines for leg strengthening

1. An exercise machine for leg strengthening, the exercise machine comprising:

a stationary frame;

a linkage;

a thigh support member and an ankle support member coupled to the stationary frame by the linkage, and configured to support a user's thigh and ankle, respectively, during a hamstring curl exercise motion;

wherein the linkage is configured such that the thigh support member and the ankle support member are each movable with respect to the stationary frame during the hamstring curl exercise motion, thus facilitating contraction and extension of both of a hamstring and glute of the user during the hamstring curl exercise motion;

wherein the linkage is configured such that contraction and extension of both of the hamstring and glute during the hamstring curl exercise motion causes the ankle support member to pivot relative to the thigh support member, and causes both of the ankle support member and the thigh support member to pivot relative to the stationary frame; and

a resistance mechanism coupled to the linkage and configured to resist pivoting movement of the ankle support member relative to the thigh support member and configured to resist pivoting movement of both of the ankle support member and thigh support member relative to the stationary frame.

2. The exercise machine according to claim 1 , wherein the linkage couples the thigh support member to the stationary frame such that the contraction and extension of the user's thigh during the hamstring exercise motion causes the thigh support member to pivot about a rear fixed pivot axis, which remains stationary with respect to the stationary frame.

3. The exercise machine according to claim 2 , wherein the linkage comprises a rear pivot arm that couples the thigh support member to the stationary frame such that the rear pivot arm and the thigh support member pivot together about the rear fixed pivot axis.

4. The exercise machine according to claim 3 , wherein the thigh support member extends transversely from the rear pivot arm.

5. The exercise machine according to claim 3 , wherein the linkage comprises a forward pivot arm that couples the ankle support member to the rear pivot arm at a first movable pivot axis, which pivots about the rear fixed pivot axis, along with the rear pivot arm, wherein the contraction and extension of the user's hamstring during the hamstring exercise causes the ankle support member to pivot about the first movable pivot axis.

6. The exercise machine according to claim 5 , wherein the ankle support member extends transversely relative to the forward pivot arm.

7. The exercise machine according to claim 6 , further comprising an ankle support member adjustment device that facilitates adjustment of the ankle support member into and between a plurality of fixed positions relative to the forward pivot arm.

8. The exercise machine according to claim 7 , wherein the ankle support adjustment device comprises a plate on a first one of the forward pivot arm and the ankle support member and a spring-loaded pin on a second one of the forward pivot arm and the ankle support member, and wherein the spring-loaded pin engages with each of a plurality of holes in the plate to thereby fix the ankle support member into a corresponding one of the plurality of fixed positions.

9. The exercise machine according to claim 5 , wherein the linkage further comprises an intermediate pivot arm that couples the forward pivot arm to the stationary frame at a forward fixed pivot axis, which remains stationary with respect to the stationary frame, and such that contraction and extension of the user's hamstring during the hamstring exercise causes the ankle support member, the forward pivot arm, and the intermediate pivot arm to pivot about the forward fixed pivot axis.

10. The exercise machine according to claim 9 , wherein the intermediate pivot arm is coupled to the forward pivot arm at a second movable pivot axis that is located forwardly of the first movable pivot axis; and wherein contraction and extension of the user's hamstring and glute during the hamstring curl exercise causes the second movable pivot axis to pivot about the first movable pivot axis and causes the first movable pivot axis to pivot about the rear fixed pivot axis.

11. The exercise machine according to claim 10 , wherein the intermediate pivot arm has forward and rearward ends and an intermediate portion that extends between the forward and rearward ends, and wherein the first movable pivot axis is located at the forward end of the intermediate pivot arm.

12. The exercise machine according to claim 11 , wherein the intermediate pivot arm is coupled to the forward pivot arm by opposing axle ends that transversely extend relative to opposite sides of the intermediate pivot arm and are supported by opposing supporting arms of the forward pivot arm.

13. The exercise machine according to claim 11 , further comprising a resistance mechanism that resists pivoting movement of the thigh support member and the ankle support member, respectively, during the hamstring curl exercise motion.

14. The exercise machine according to claim 13 , further comprising a manual assist lever fixed to the linkage along the rearward fixed pivot axis, the manual assist lever facilitating another user to manually assist the hamstring curl exercise motion.

15. The exercise machine according to claim 14 , wherein the manual assist lever is on an opposite side of the stationary frame relative to the linkage.

16. The exercise machine according to claim 1 , wherein the stationary frame is configured for the user to perform the hamstring curl exercise motion in a standing position and further comprising a handle member located above the thigh and the ankle support members.

17. The exercise machine according to claim 1 , further comprising a platform on which the user stands while performing the hamstring curl exercise motion.

18. The exercise machine according to claim 17 , wherein the platform has a height that is adjustable with respect to the stationary frame.

19. The exercise machine according to claim 18 , further comprising a platform frame that supports the platform in a plurality of vertical positions with respect to the stationary frame, and a lift handle on the platform, the lift handle being engage-able with the platform frame to retain the platform in each of the plurality of vertical positions at the plurality of vertical positions.

20. The exercise machine according to claim 19 , wherein the lift handle extends from a side of the platform and can be retained in each one of a plurality of stepped recesses formed in the platform frame.

21. The exercise machine according to claim 19 , further comprising a gas cylinder that assists movement and positioning of the platform with respect to the platform frame.

22. The exercise machine according to claim 21 , wherein the gas cylinder has a first end coupled to the platform and a second end coupled to the platform frame, and wherein the gas cylinder extends transversely to and beneath the platform.

23. An exercise machine for leg strengthening, the exercise machine comprising:

a stationary frame;

a thigh support member and an ankle support member coupled to the frame and configured to support a user's thigh and ankle, respectively, during a hamstring curl exercise motion;

wherein the thigh support member and the ankle support member are each movable with respect to the stationary frame during the hamstring curl exercise motion, thus facilitating contraction and extension of both of a hamstring and glute of the user during the hamstring curl exercise motion; and

a linkage that couples the thigh support member to the stationary frame such that the contraction and extension of the user's thigh during the hamstring exercise motion causes the thigh support member to pivot about a rear fixed pivot axis, which remains stationary with respect to the stationary frame;

wherein the linkage comprises a rear pivot arm that couples the thigh support member to the stationary frame such that the rear pivot arm and the thigh support member pivot together about the rear fixed pivot axis; and

wherein the rear pivot arm has a rearward end that is coupled to the stationary frame by opposing axle ends that transversely extend relative to opposite sides of the rear pivot arm and are supported by opposing supporting arms of the stationary frame.

24. The exercise machine according to claim 23 , wherein the rear pivot arm has a forward end that is parallel to the rearward end, and a middle portion that is angular relative to the forward and rearward ends.

25. An exercise machine for leg strengthening, the exercise machine comprising:

a stationary frame;

a thigh support member and an ankle support member coupled to the frame and configured to support a user's thigh and ankle, respectively, during a hamstring curl exercise motion;

wherein the thigh support member and the ankle support member are each movable with respect to the stationary frame during the hamstring curl exercise motion, thus facilitating contraction and extension of both of a hamstring and glute of the user during the hamstring curl exercise motion;

a linkage that couples the thigh support member to the stationary frame such that the contraction and extension of the user's thigh during the hamstring exercise motion causes the thigh support member to pivot about a rear fixed pivot axis, which remains stationary with respect to the stationary frame;

wherein the linkage comprises a rear pivot arm that couples the thigh support member to the stationary frame such that the rear pivot arm and the thigh support member pivot together about the rear fixed pivot axis;

wherein the linkage comprises a forward pivot arm that couples the ankle support member to the rear pivot arm at a first movable pivot axis, which pivots about the rear fixed pivot axis, along with the rear pivot arm, wherein the contraction and extension of the user's hamstring during the hamstring exercise causes the ankle support member to pivot about the first movable pivot axis;

wherein the linkage further comprises an intermediate pivot arm that couples the forward pivot arm to the stationary frame at a forward fixed pivot axis, which remains stationary with respect to the stationary frame, and such that contraction and extension of the user's hamstring during the hamstring exercise causes the ankle support member, the forward pivot arm, and the intermediate pivot arm to pivot about the forward fixed pivot axis;

wherein the intermediate pivot arm is coupled to the forward pivot arm at a second movable pivot axis that is located forwardly of the first movable pivot axis; and wherein contraction and extension of the user's hamstring and glute during the hamstring curl exercise causes the second movable pivot axis to pivot about the first movable pivot axis and causes the first movable pivot axis to pivot about the rear fixed pivot axis; and

wherein the intermediate pivot arm has forward and rearward ends and an intermediate portion that extends between the forward and rearward ends, and wherein the first movable pivot axis is located at the forward end of the intermediate pivot arm; and

a resistance mechanism that resists pivoting movement of the thigh support member and the ankle support member, respectively, during the hamstring curl exercise motion;

wherein the resistance mechanism comprises a cam that rotates with the intermediate pivot arm about the second pivot axis.

26. The exercise machine according to claim 25 , wherein the resistance mechanism comprises an elongated pulley member having a first end coupled to a resistance weight and a second end coupled to the cam.

27. The exercise machine according to claim 26 , wherein the resistance weight is part of a weight stack.

28. The exercise machine according to claim 26 , wherein the cam comprises a cam surface having a curved profile along which the elongated pulley member engages as the cam is rotated with the linkage about the second pivot axis.

29. The exercise machine according to claim 26 , further comprising a resistance member adjustment device that facilitates positioning of the intermediate pivot arm with respect to the cam into and between a plurality of fixed positions.

30. The exercise machine according to claim 29 , wherein the resistance member adjustment device comprises a spring-loaded pin on the intermediate pivot arm and a plurality of holes in the cam, wherein the spring-loaded pin engages with each of a plurality of holes in the cam to thereby fix the intermediate pivot arm into a corresponding one of the plurality of fixed positions.

31. An exercise machine for leg strengthening, the exercise machine comprising:

a stationary frame;

a thigh support member and an ankle support member coupled to the frame and configured to support a user's thigh and ankle, respectively, during a hamstring curl exercise motion;

wherein the thigh support member and the ankle support member are each movable with respect to the stationary frame during the hamstring curl exercise motion, thus facilitating contraction and extension of both of a hamstring and glute of the user during the hamstring curl exercise motion;

a platform on which the user stands while performing the hamstring curl exercise motion, wherein the platform has a height that is adjustable with respect to the stationary frame; and

a platform frame that supports the platform in a plurality of vertical positions with respect to the stationary frame, and a lift handle on the platform, the lift handle being engage-able with the platform frame to retain the platform in each of the plurality of vertical positions at the plurality of vertical positions;

wherein the platform frame comprises an angular slide bar on an opposite side of the platform with respect to the lift handle and extending transversely relative to the platform, and further comprising a sleeve that slides along the angular slide bar and facilitates horizontal positioning of the platform upon engagement of the lift handle with the platform frame at one of the vertical positions.