in the following detailed description , reference is made to the accompanying drawings which form a part hereof , and in which is shown by way of illustration specific embodiments in which the invention may be practiced . these embodiments are described in sufficient detail to enable those of ordinary skill in the art to make and use the invention , and it is to be understood that structural , logical , or procedural changes may be made to the specific embodiments disclosed without departing from the spirit and scope of the present invention . refer now to fig1 through 3 , which illustrate an embodiment of the present invention . a treadmill 10 has a desired length l and width w of a walking surface 15 . two safety rails 20 are mounted longitudinally along both lateral sides of the treadmill 10 . they are mounted on vertical supports 22 above the treadmill walking surface 15 at a height h within an arm &# 39 ; s reach of the user when the treadmill 10 is in use . the safety rails 20 may be grasped by the user to obtain stability on the treadmill 10 . the safety rails 20 are also used for anchoring a safety belt 25 that may be worn around a user &# 39 ; s waist to inhibit the user from falling down onto the running surface of the treadmill . the safety belt 25 will be described in further detail below . along the left and right lateral sides of the treadmill 10 , there are respective left and right work surfaces 30 , 40 . a control panel 45 for the treadmill 10 is shown recessed into the right work surface 40 , although it may be located elsewhere within arm &# 39 ; s reach of the user . at the front of the treadmill , there is a front work surface 50 . the front work surface 50 may be tilted , as shown in fig2 , in an adjustable fashion such that a user may face work materials at a selected angle . along the perimeter of all work surfaces 30 , 40 , 50 , there is a pencil stop ledge 35 . all of the work surfaces 30 , 40 , 50 are placed at a height z above the surface 15 that is convenient to the user for working . the left and right work surfaces 30 , 40 have a depth v and length y and the front work surface 50 has a depth d and a length x sufficient for placing desired office working materials such as papers , books , office supplies , a telephone , and a computer . fig4 illustrates a plan view of the safety belt 25 in an engaged position . the safety belt 25 has a belt portion 125 for wearing around the user &# 39 ; s waist , and has a first plate 111 that , on a first side , attaches the belt portion 125 to an attachment cord 112 which is anchored to the safety rail 20 . on a second side of the belt portion , padding 113 may be provided to prevent the plate 111 from rubbing against the user and increase the comfort of the user . the safety belt 25 also has a draw string 114 for adjusting the length of the belt portion 125 according to the width of the user &# 39 ; s waist . if the user &# 39 ; s waist is thicker , the draw string 114 may be adjusted to accommodate the user &# 39 ; s waist . if the user &# 39 ; s waist is thinner , the draw string 114 may be pulled to narrow the safety belt 125 to accommodate the user &# 39 ; s waist , and tied to hold the adjustment . the safety belt 25 also includes a locking mechanism 115 attached to a second plate 121 for locking the safety belt onto the user &# 39 ; s waist . to remove the safety belt 25 , the locking mechanism 115 may be disengaged , by flipping the locking mechanism 115 over , as shown in fig5 , thereby releasing the second plate 121 to unlock the safety belt 125 . fig6 through 8 and fig1 are views of a portion of the safety rail 20 . the safety rail 20 has a trench 225 opening to the top surface of the rail 20 . the trench 225 has within it holes 226 at spaced at a predetermined distance p from each other . a j - bracket attachment 130 curls over the rail 20 and has a stopper 135 that engages a lip portion 137 to inhibit the attachment 130 from being entirely removed from the rail 20 during use . the attachment 130 also has a tab 131 that sits within the trench 225 . when the attachment 130 is moved along the rail 20 and placed at a desired location along the rail 20 , the tab 131 sits within a hole 226 in the trench 225 , anchoring the attachment 130 at that location . to move the attachment 130 to a different location along the trench 225 , the attachment 130 may be disengaged by lifting the attachment 130 so that the tab 131 is fully withdrawn from the hole 226 and the attachment 130 may slide along the rail 20 to another hole 226 , as shown in fig9 . fig1 and 12 illustrate another embodiment of the present invention . a treadmill 110 is shown having pipe handrails 120 mounted longitudinally along both lateral sides of the treadmill 110 . the pipe handrails 120 are mounted above the treadmill 110 at a height k . the safety belt 325 is suspended from the handrails 120 by a pair of slide rings 124 which slide along the pipe handrails 120 . when worn around a user &# 39 ; s waist , the safety belt 325 provides additional protection against the user falling down onto the running surface of the treadmill 110 . the safety belt 325 is anchored by the attachment cord 112 to the pipe handrails 120 at a height k sufficient to inhibit the torso of a fallen user from severely impacting the treadmill surface 315 . this embodiment is particularly desirable for inhibiting heavier users from falling down and making injurious bodily contact with the running surface 315 of the treadmill 110 . the dimensions and materials of the attachment cord 112 , the vertical supports 22 , the rails 120 , the rings 124 and the belt 325 , and associated structure are engineered to have sufficient strength to accomplish this purpose . the pipe handrail 120 has an outer diameter φ 1 and may be raised to a height along the treadmill such that it will support a user from falling down onto the surface 315 of the treadmill 110 . the height k and length of the attachment cord 112 may be adjustable for accommodating different size users . for example , the vertical supports 22 may have telescoping sections that can be fixed at different heights with hole and pin arrangements ( not shown ). a slide ring 121 having an inner diameter φ 2 attaches to a safety belt and slides freely along the pipe handrail 120 . the inner diameter φ 2 of slide ring 121 is greater than the outer diameter φ 1 of the pipe handrail 120 . it should be noted that although the pipe handrail 120 and slide ring 121 are both illustrated with a generally circular configuration , the invention is not limited to such a configuration . the pipe handrail may have a square , elliptical , rectangular or other configuration and the slide ring may have the same or a different configuration while maintaining an inner dimension that is larger than the outer dimension of the pipe handrail so that the slide ring may slide back and forth along the pipe handrail . if a computer monitor 55 , other computer accessories , and / or a telephone 56 are desired on the work surfaces 132 , 140 , 150 , the work surfaces 132 , 140 , 150 may optionally be provided with holes through which wiring may connect to a hard drive that may be stored under the work surface or other wall sockets . the work surfaces 132 , 140 , 150 may also be provided with recesses for placement of the surface - top accessories . while various embodiments of the present invention have been described above , it should be understood that they have been presented by way of example , and not limitation . it will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the present invention . thus , the present invention should not be limited by any of the above - described exemplary embodiments .
a treadmill system having a side work surface at a height convenient for a user access for working . the treadmill also has a safety rail that runs longitudinally . a safety belt that may be worn by a user is anchored to the side rail . in one embodiment , the side rail height and the belt are configured to support the weight of the user in case of a fall .