The present invention relates to a buoyancy suit to be worn by an individual during exercise in water, and in particular to a suit of this type configured to enable the individual to be monitored during exercise.

The present invention is applicable particularly, although not necessarily exclusively, in relation to exercise of the type often referred to as "deep water aqua jogging", which is becoming recognised as being highly beneficial both for fitness and for rehabilitation. Aqua jogging is done in water - typically in a pool - but differs from swimming in that the torso is maintained upright or at least semi-upright. The participant may for example make movements which mimic a running action, although the water is typically (although not always) deep enough that the feet do not contact the floor of the pool. The water provides resistance to the movements of both legs and arms, simultaneously exercising multiple muscle groups and making it possible to burn calories at a high rate. The participant may in some cases move forward through the water while exercising, or may be tethered to a fixed point on the poolside to keep them "running" on the spot.

In contrast to running on land, aqua jogging involves no impacts and has low risk of training injury. It is well suited to those with a range of physical conditions which might make other forms of exercise problematic, such as those with arthritis or back pain. Immersion of the body has the effect of reducing heart rate, making aqua jogging well suited to cardiac patients and sufferers from hypertension. It is also used in rehabilitation after injury.

A buoyancy suit for use in aqua jogging is described in granted United Kingdom patent GB2475516B, being configured to be worn on the upper torso and around the pelvis and provided with floatation above the wearer's centre of gravity, thereby urging the wearer toward an upright position. The buoyancy suit thus helps to support the wearer with the head above water and in the generally upright position needed for the exercises.

It is common in relation to land based exercise regimes to provide for monitoring of performance. Thus for example gymnasium equipment often includes sensors for heart rate measurement and may estimate calorie burn during exercise. At a more sophisticated level, a range of technologies is applied to the assessment of fitness and performance of athletes, including use of sensors worn on the body for the measurement of numerous biomechanical aspects of performance and of indicators of cardiovascular function. By contrast, assessment of performance during deep water aqua jogging is typically reliant on observation by a trainer. According to a first aspect of the present invention there is provided a buoyancy suit which is to be worn by an individual during exercise in water and is provided with at least one float, the buoyancy suit incorporating a plurality of sensors configured to monitor the individual during said exercise, and an interface for outputting data obtained from the sensors to a processing device for analysis.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawing, which is a front view of a buoyancy suit embodying the present invention.

The depicted buoyancy suit 10 is adapted to be worn on the person during exercise in water and comprises a body suit 12 and floats 14. The body suit 12 comprises flexible membranous material which may be impermeable to water or may be water permeable. In the present embodiment the material of the body suit 12 is neoprene and the suit is somewhat akin to a wetsuit in its construction and is able to maintain an insulative layer of water next to the wearer's skin. Other types of suit construction may be used in other embodiments of the invention.

The body suit 12 is configured in the present embodiment to be worn over the torso, shoulders, upper arms, pelvic area and upper legs. The example depicted does not extend to the lower arms and lower legs of the wearer, but in other embodiments such additional coverage may be provided. A closure such as a zip may be provided to facilitate donning and doffing of the body suit 12, but is not seen in Figure 1.

The floats 14 may for example comprise buoyant foam material received in pockets formed by the body suit 12. Other modes of construction are possible in further embodiments of the invention. The distribution of the floats is such as to urge the wearer, whilst floating, toward an orientation in which his/her torso is generally upright, the majority of the floats' displacement being disposed above the wearer's centre of gravity. In the illustrated embodiment floats 14a-14c are arranged on the torso portion of the body suit 14 and further floats 14d, 14e are provided on the shoulder and upper arm regions respectively.

The body suit 10 may be provided with an attachment for a tether. As explained above, the tether can be led to a fixed point on the poolside, enabling the wearer to carry out running type exercise without moving through the water. The tether is provided on the rear of the suit and is not seen in the drawing, but may for example take the form of a ring or other attachment means disposed mid way up the torso portion of the rear of the body suit 12. An example of a tether attachment is provided in the above mentioned prior art document GB2475516, to which the attention of the reader is directed in this respect. In accordance with the present invention, the buoyancy suit 10 is provided with a number of sensor modules at selected positions, to monitor aspects of the wearer's performance during exercise in water.

Some of the sensor modules are for measuring motion of parts of the body, being sensitive to acceleration and/or to rotational motion and/or to their own orientation. In the present embodiment, these motion/orientation sensitive modules are provided:

- on left and right upper arms portions 18 of the body suit 12, these modules being designated 16a;

- on trunk portion 20 of the body suit 12. There are four of these modules in the illustrated example - a module 16b centrally placed on the upper torso, a pair of modules 16c, 16d mid-way down the torso on the left and right sides respectively and a module 16e at or above the groin region; and

- on left and right upper leg portions 22 of the body suit 12, these modules being designated 16f, 16g.

Provision of motion/orientation sensors on individual limbs makes it possible to sense motion of those limbs to provide for biomechanical analysis of movement by the wearer. Sensor modules on the trunk indicate the orientation and motion of that part of the body, and potentially of changes in its curvature during exercise.

The number and physical arrangement of the motion/orientation sensors 16 can differ in other embodiments of the invention. For example, in versions of the body suit 12 which extend to the lower arms and lower legs of the wearer, modules may be provided on these portions of the suit. The extent of motion of the lower arms and legs is of course greater than that of the upper arms and legs, and in addition provision of motion/orientation sensor modules on both the lower and the upper parts of the leg or arm makes it possible to measure movement of the knee or elbow joint.

The sensor modules 16 of the present embodiment each comprise: a three axis magnetometer which provides an indication of sensor orientation (by reference to the Earth's magnetic field); a three axis gyroscope sensitive to rotational motion of the sensor; and a three axis accelerometer which measures acceleration and, by techniques including integration, and along with data from the other sensors, is able to be used to establish movement of the sensor. By virtue of the mounting of the sensor modules 16 on the body suit 12, they move along with the body of the wearer during exercise, and movements, rotations and the inclination of the sensor modules 16 can be used to determine movements, rotation and orientation of the trunk and limbs of the wearer.

Miniature sensors suitable for use in the modules 16 are widely available and are known to the skilled person, so these aspects of the present embodiment will not be described in detail herein.

According to the present invention the buoyancy suit 10 is capable of measuring aspects of the wearer's performance not limited to bodily movement. In particular, indicators of cardiovascular performance may be measured. The illustrated buoyancy suit 10 has sensors 24 for measuring oxygen saturation in the wearer's bloodstream and also for measuring pulse rate (heart rate). In the present embodiment these take the form of pulse oximeters 24a, 24b, 24c and 24d disposed on respective cuff portions 26 on the arm and leg parts of the body suit 12. These cuff portions can be close fitting, to place the sensors 24 in close relationship with the skin of the wearer. The same sensor units 24 can be provided with temperature sensors to measure local skin temperature.

An echo cardiogram type sensor (not shown), e.g. an ultrasound based device, may additionally be provided. This can be carried in the trunk portion 20 of the body suit 10, or may be carried on a tight fitting inner part worn within the body suit 12.

According to the present embodiment the sensor modules 16 are connected through a network of wires (not shown) to a common module 28. The wires may be led through suitable passages in the suit, e.g. formed by pockets in its membranous material. In the present embodiment the common module 28 comprises a power supply in the form of an electrical battery and power is supplied through the said wires to each of the sensor modules 16. In other embodiments individual sensor modules 16 may for example be provided with their own power supply, or may be driven, kinetically or otherwise, by the bodily motion of the wearer. The wires also serve to conduct sensor outputs from the sensor modules 16, 24 to the common module 28.

The common module 28 collates the sensor outputs and transmits a corresponding data set to a separate processing device. The data set may comprise the outputs of the sensor modules 16, 24 in their entirety. Alternatively the common module 28 may carry out some processing of the sensor data prior to transmission, e.g. to reduce the volume of data transmitted. The data transmission may be made through a wireless connection. The required data transfer connection may be a radio frequency connection. It may use the Bluetooth ^® communications standard. Transmission of electromagnetic signals can be impaired by passage through water. According to the present embodiment this problem is alleviated by transmitting the required signal from an antenna 32 in the upper region of the suit which is subject only to shallow or occasional immersion. The antenna may be disposed in a collar part 30 of the body suit 12 or it may project upwards form this collar part, e.g. at the back of the wearer's neck, as depicted. In the present embodiment the common module 28 is also disposed in the collar part 30 of the body suit 12, although it may be differently sited in other embodiments of the present invention.

The buoyancy suit 10 may, instead of or in addition to a wireless data transmission facility, be configured to output sensor data through a wired connection via the aforementioned tether. The term "wired" in this instance implies a physical connection for transmission of data but is not limited to electrical wiring as such - the connection could for example by fibre optic. In such an embodiment the tether attachment may include a plug or socket for connection to wiring led through the tether itself.

Sensor data output from the buoyancy suit 10 is received by a separate receiver 34 for analysis. Analysis may be carried out locally, e.g. in the case where the receiver 34 is part of a processing device such as a tablet computer. Alternatively or additionally, the sensor data may be transmitted to a remote server for analysis and/or storage. Thus for example the software for analysis of the sensor data may be implemented on a remote server connected to the receiver 34 through a wide area network (which may be the internet). Whether the analysis is carried out locally or remotely, a user (such as a trainer) may be provided with real time or at least near real time performance metrics, e.g. through a hand held processing device, during a training session.

Where the sensors 16, 24 and the common module 28 are driven from one or more rechargeable batteries, provision must be made for these to be recharged after use. In some embodiments the buoyancy suit 10 may be provided with an electrical connector for connection to a charger, but since the suit is for use in water this must be provided with a suitable sealable enclosure. In the present embodiment this potentially problematic connection is dispensed with, the suit instead being adapted to receive electrical power through an inductive coupling to charge its onboard battery. Such wireless charging technology is known of course in relation to other types of device. The required transmitter may be provided in a hanging rail, so that after use the buoyancy suit 10 can simply be hung on the charging rail to dry out and to charge.

The above described embodiment is presented by way of example and not limitation. Any number of modifications and variations is possible without departing from the scope of the present invention as claimed. For example the nature of the sensors, and the sensed quantities, may differ in other embodiments. The suit may be simplified by dispensing, in some or all of the sensor modules 16, with one or more of the accelerometers, the magnetometers or the gyroscopes. It may additionally incorporate fluid pressure sensors for monitoring water pressure. Such sensors may measure hydrostatic pressure (depth) and/or may measure pressure created dynamically, by movement of the wearer, to provide information about movement and/or about energy expended. Sensors used to detect bodily movement may, in addition or alternatively to the sensor modules 16 described above, use piezoelectric technology. Suitable piezoelectric sensors may be arranged to sense local flexure of the buoyancy suit 10, e.g. in the region of joints.

The tether used to restrain forward motion of the wearer may incorporate a sensor to detect tension in the tether (e.g. in the form of a strain gauge), which represents the force that the wearer is exerting to urge themselves forwards. The tether may be led to a fixed point poolside, or may be connected to a second person to introduce a competitive "tug of war" element to a training session.

The buoyancy suit 10 may incorporate an indoor location device in order to monitor movement through the water, providing metrics such as velocity, distance travelled in a session and so on.