referring to fig1 and fig2 , a neck muscle exercising or performance assessment device 10 comprises a helmet 20 to the top of which a bearing flange 30 is fixedly attached by cables 35 secured to rivets 37 in the helmet 20 . rotatably mounted on the bearing flange 30 is a rod 40 extending radially outward from an axis a through the a point of rotation b where one end of the rod 40 is rotatably secured in a rotational bearing secured in the bearing flange 30 . the rod 40 has a 90 ° bend 42 proximate the end secured at point of rotation b so that the rod 40 may revolve around the axis a while pointing radially outward form the axis a . the rod 40 is threaded along part of its length with screw threads 43 for matingly receiving nuts 44 that secure demountable weight 46 near a far end 47 of the rod 40 . there is one nut 44 on each side of the weight 46 , the weight 46 comprising a central aperture through which the rod 40 is inserted . the device 10 further comprises a counter including a magnet 50 from a bicycle speedometer mounted on the rod 40 in communication through wire 53 with a bicycle speedometer 55 for counting the number of full revolutions of the rod 40 around the axis a . a chin strap 60 securely holds the helmet 20 on the head of a subject . fig2 depicts a magnified view of the rod 40 rotatably mounted on the bearing flange 30 by a rotational bearing 32 in the bearing flange 30 . the bearing flange 30 comprises securement bolts 33 for securing the cables 35 to the bearing flange 30 . in use , a subject puts on the helmet 20 and secures the chin strap 60 under his chin in the same manner as donning any helmet of similar nature . by rotating his head clockwise or counter - clockwise in a rhythmic and orbital fashion , the subject can induce the rod 40 to begin revolving around the axis a by virtue of being rotatably mounted on the bearing flange 30 . the weight 46 being located proximate the far end 47 of the rod 40 provides a heightened moment of inertia and increases centripetal force on the rod 40 , which provides increased resistance to neck muscles of the subject . the increased resistance exercises the neck muscles more vigorously . more or less resistance may be provided by adding more weight or adjusting the length of the rod , some variations of which are shown in fig3 a - c . the subject may follow a prescribed regimen and the counter may be used to ensure that the subject accurately follow the regimen . the device may be used for exercise only or for performance assessment . in one aspect , the device may be used to assess the risk of concussion . risk of concussion may be assessed and determined by correlating a subject &# 39 ; s ability to perform on the device i . e . time needed to complete a pre - determined number of revolutions on the device at a specified weight and rotatable arm length and concussion risk . the more time a subject requires to perform the pre - determined number of revolutions , the weaker and less responsive his / her neck may be and therefore the more prone he / she may be to concussion . as an example , when assessing the performance of a team of hockey players on the device and then following this team during a hockey season , those who perform more poorly on the device may have an increased likelihood of suffering a concussion . if this is the case then it is likely that a certain performance level will be associated with the natural baseline risk for suffering a concussion and that performance levels below this line will be at higher risk for concussion . it may therefore be possible to screen players of nearly any sport to determine those that are at a high and or higher risk of concussion . in the event of an injury , a player who has suffered a concussion or whiplash may have a drop in performance on the device as the muscles of the neck are commonly injured during a concussion , and always during whiplash . therefore , the device can be used to assess when a player is ready to return to sport after suffering a concussion by delaying return to sport until the player is able to perform on the device to the previously described baseline . fig3 a - 3b depict a telescoping rod 140 comprising an outer rod 141 having a 90 ° elbow 142 and an inner rod 145 that may telescope within the outer rod 141 . the outer rod 141 is rotatably mounted to a bearing flange ( not shown ) at a proximal end 143 . the outer rod 141 comprises a series of apertures 146 arranged along a length of the outer rod 141 for receiving a spring - loaded pin 147 situated near a proximal end of the inner rod 145 . the spring - loaded pin 147 may be engaged in any one of the apertures 146 to adjust the overall length of the rod 140 . to adjust the length of the rod 140 , the spring - loaded pin 147 is depressed to disengage the pin 147 from an aperture 146 and the inner rod 145 is slid proximally or distally within the outer rod 141 until the spring - loaded pin 147 engages the next aperture 146 . the outer rod 141 may comprise any number of apertures 146 , and each aperture represents a length setting for the rod 140 . the telescoping rod 140 may be of any desired length , for example 12 inches in the fully extended configuration ( fig3 a ) and 6 inches in the fully retracted configuration ( fig3 b ). weights , for example two weights 151 , 152 as seen in fig3 a or one weight 151 as seen in fig3 b , may be mounted on the inner rod 145 . to secure the weights 151 , 152 on the inner rod 145 , securement clips 153 may mounted on the inner rod 145 , the clips 153 having ends that may be inserted through clip apertures 154 on the inner rod 145 . two clips 153 may be used on each side of the weight or weights ( e . g . weights 151 , 152 as seen in fig3 a , or weight 151 as seen in fig3 b ). only one clip distally of the weight may be needed if the inner rod is retracted sufficiently that the outer rod helps secure the weight or weights in place proximally . the inner rod 145 may comprise a series of any number of clip apertures 154 , and may comprise an opposed series of clip apertures , the opposed clip aperture receiving opposite ends of the securement clips 153 . a series of clip apertures 154 permits mounting the weights 151 , 152 at a variety of positions along the inner rod 145 in order to change the moment of inertia for the device on which the rod 140 is mounted . fig3 c depicts a second embodiment of a telescoping rod 240 comprising an outer rod 241 having a 90 ° elbow 242 and an inner rod 245 that may telescope within the outer rod 241 . the outer rod 241 is rotatably mounted to a bearing flange ( not shown ) at a proximal end 243 . the telescoping rod 240 comprises a spring - loaded pin 247 near a proximal end of the inner rod 245 , and apertures 246 in the outer rod 241 to engage the spring - loaded pin 247 in a manner similar to that of the telescoping rod 140 described in relation to fig3 a - b . however , instead of the inner rod 245 possessing clip apertures , at least a portion of the inner rod 245 comprises screw threads 255 onto which weights 250 , 251 , 252 may be threaded . the weights may be secured at any position along the threaded portion 255 by nuts , for example a wing nut 253 distal of the weights 250 , 251 , 252 , and if desired , another nut on the proximal side of the weights 250 , 251 , 252 . the weights 250 , 251 , 252 may be threaded to any desired location along the threaded portion 255 to change the moment of inertia of the device . fig4 a and 4b depict different embodiments of attachment mechanisms for mounting a bearing flange on headwear , for example a helmet . in fig4 a , a bearing flange 130 comprising a rotational bearing 132 has straps 135 mounted therein by feeding the straps 135 through through - apertures 136 in edges of the bearing flange 130 . alternatively , instead of two straps there could be four straps , each strap attached to the bearing flange . the straps may alternatively be secured to the bearing flange on an upper or lower surface of the flange rather than an edge or edges . the straps 135 may be configured so that straps or parts of straps are situated on opposed sides of the bearing flange 130 for better securement efficiency . the straps 135 may be secured to the headwear by bolts , rivets , stitching and the like at securement structures 137 on the straps 135 , preferably proximate ends of the straps 135 . any number or arrangement of straps may be used to ensure proper securement of the bearing flange 130 on the headwear . in fig4 b , a bearing flange 230 comprising a rotational bearing 232 has lever buckles 237 attached thereto . the lever buckles 237 comprise lever handles 239 pivotally mounted on the lever buckles 237 and operatively connected to hooks 238 through connecting straps 236 . the hooks 238 are configured to engage mounting struts 233 mounted to headwear ( e . g . a helmet ) ( not shown ). the mounting struts 233 may be secured to the headwear , for example with u - bolts or clips . the mounting struts 233 are spaced apart such that when the lever handles 239 are in an “ up ” position , the connecting straps 236 have sufficient length for the hooks 238 to hook over the mounting struts 233 , as seen in the lower part of fig4 b . when the lever handles 239 are in a “ down ” position with the hooks 238 hooked over the mounting struts 233 , the connecting straps 236 are pulled toward the buckles 237 tightening the hooks 238 on the mounting struts 233 , as seen in the upper part of fig4 b . any number and arrangement of lever buckles may be used to ensure proper securement of the bearing flange 230 on the headwear . mounting struts may be located anywhere on the headwear and a plurality of mounting struts on the headwear offer the opportunity for mounting the bearing flange in different locations . advantageously , the attachment mechanisms for mounting the bearing flange on headwear are readily removable and re - mountable to permit exchange of headwear or to move the bearing flange to a different location on the headwear . the novel features will become apparent to those of skill in the art upon examination of the description . it should be understood , however , that the scope of the claims should not be limited by the embodiments , but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole .
training neck muscles in such a way as to improve responsiveness to head acceleration forces , and to help prevent concussion and / or screen subjects who are at high risk of concussion , especially from contact sports , the neck muscles may be trained to improve strength and responsiveness to head acceleration . this may be accomplished by a device and / or method of training that incorporates an adjustable centripetal force about a fixed axis on the head . the centripetal force may be adjusted through varying the weight and / or length of a force arm . neck muscle performance may be measured by the number of revolutions of the force arm completed over a pre - determined time period or the time required to complete a pre - determined number of revolutions of the force arm .