Dataset of the front-wheel load of a set of wheelchair propulsion experiments

Twenty-five participants (19 females, mean age (S.D) = 30 (10) years, mean body mass = 68 (11) kg, height = 170 (7) cm) with no wheelchair experience were included in the study. Participants propelled the hand-rims of a wheelchair on a large (3.0 x 5.0 m) motor-driven treadmill, while their kinematics were measured with three IMUs (attached to the participants’ sternum, the wheelchair’s frame, and right wheel axle) and the front-wheel load was measured using custom-made load pins (in both front wheel axes). Before the treadmill sessions, participants received a 10-minute overground wheelchair training to get familiar with the wheelchair and a 10-minute training on the treadmill (see Fig. 1). After three treadmill sessions, drag tests were performed on the treadmill to obtain rolling resistance coefficients of the (small) front and (large) rear wheels.<br>To simulate different wheelchair characteristics and push styles, the treadmill session was repeated six times with different tire pressures (1.75 bar, 3.5 bar, 5.25 bar) or added mass (0 kg, 5 kg, 15 kg), see Fig. 1, and with three pushing styles (no trunk motion at 1.2 m/s [style 1], normal trunk motion at 1.2 m/s [style 2], normal trunk motion at 1.7 m/s [style 3]). By following a metronome (25 beats/min in pushing style 1 and 40 beats/min in pushing style 2 and 3), participants were stimulated to make long pushes accompanied by ‘natural’ trunk motion. Each treadmill session consisted of 30s familiarization to the new situation, after which participants propelled 60s in each pushing style. In this way, a dataset was composed of eighteen (three push styles and six treadmill sessions) 60s-time trials per participant. The order of the treadmill sessions differed per participant.<br>The load on the front wheels is expressed as percentage of the total weight (of participant + wheelchair).<br>The dataset consists of 11 columns representing the following variablesv_wc: linear velocity of the wheelchair in m/sa_wc: linear acceleration of the wheelchair in m/s^2av_tr: Angular velocity of trunk (around sagittal axis) in rad/saa_tr: Angular acceleration of trunk (around sagittal axis) in rad/s²ang_tr: Trunk inclination angle in radlaz_tr: Trunk acceleration perpendicular to the frontal plane of the trunk in m/s²lay_tr: Trunk caudal-cranial acceleration in m/s²lar_tr: Magnitude of trunk acceleration vector in m/s²F: front wheel-load as percentage of the total weight (of participant + wheelchair)subjectnr: subject numberblocknr: block number in whichblock 1: rear wheel tyre pressure = 5.25; added mass = 0 kg (practice/familiarization session)block 2: rear wheel tyre pressure = 5.25; added mass = 5 kgblock 3: rear wheel tyre pressure = 5.25; added mass = 15 kgblock 4: rear wheel tyre pressure = 5.25; added mass = 0 kgblock 5: rear wheel tyre pressure = 3.50; added mass = 0 kgblock 6: rear wheel tyre pressure = 1.75; added mass = 0 kg<br>See also the file 'additional information.pdf'.

本研究纳入25名无轮椅使用经验的受试者（19名女性，年龄均值±标准差为30±10岁，体质量均值±标准差为68±11kg，身高均值±标准差为170±7cm）。受试者在尺寸为3.0×5.0m的电动跑步机上驱动轮椅手轮圈，同时通过三个惯性测量单元（Inertial Measurement Unit，IMU）——分别固定于受试者胸骨、轮椅框架以及右轮轴——采集运动学数据，并通过定制负载销（安装于两个前轮轴处）测量前轮负载。在跑步机实验前，受试者需完成10分钟地面轮椅熟悉训练，以及10分钟跑步机适应训练（详见图1）。完成三次跑步机实验后，在跑步机上开展阻力测试，以获取小型前轮与大型后轮的滚动阻力系数。

为模拟不同轮椅特性与推轮风格，本研究共进行6次重复跑步机实验，分别设置不同的轮胎气压（1.75 bar、3.5 bar、5.25 bar）与附加质量（0 kg、5 kg、15 kg），并采用三种推轮模式：1.2 m/s速度下无躯干运动（风格1）、1.2 m/s速度下正常躯干运动（风格2）、1.7 m/s速度下正常躯干运动（风格3）（详见图1）。受试者跟随节拍器（风格1为25次/分钟，风格2与3为40次/分钟）完成长距离推轮动作，并配合“自然”躯干运动。每次跑步机实验包含30秒的新环境适应阶段，随后受试者以每种推轮风格完成60秒的驱动动作。综上，每位受试者的数据集包含18组（3种推轮风格×6次跑步机实验）60秒时长的试验数据，且每位受试者的跑步机实验顺序均不相同。

前轮负载以受试者与轮椅总重量的百分比表示。

本数据集共包含11个变量列，具体如下：
v_wc：轮椅线速度，单位为m/s
a_wc：轮椅线加速度，单位为m/s²
av_tr：躯干角速度（绕矢状轴），单位为rad/s
aa_tr：躯干角加速度（绕矢状轴），单位为rad/s²
ang_tr：躯干倾斜角，单位为rad
laz_tr：躯干垂直于额状面的加速度，单位为m/s²
lay_tr：躯干尾颅向加速度，单位为m/s²
lar_tr：躯干加速度矢量的模长，单位为m/s²
F：前轮负载，以受试者与轮椅总重量的百分比表示
subjectnr：受试者编号
blocknr：实验区块编号，其中：
区块1：后轮轮胎气压=5.25 bar，附加质量=0 kg（练习/熟悉实验）
区块2：后轮轮胎气压=5.25 bar，附加质量=5 kg
区块3：后轮轮胎气压=5.25 bar，附加质量=15 kg
区块4：后轮轮胎气压=5.25 bar，附加质量=0 kg
区块5：后轮轮胎气压=3.50 bar，附加质量=0 kg
区块6：后轮轮胎气压=1.75 bar，附加质量=0 kg

详见附件文件"additional information.pdf"。