## 4 Posture and Motion
### Measuring Kinematics and Dynamics in Playing
#### 4.2.5 Other Force Measurements and Dynamometry  
Forcedplate Measurements can be used to monitor the foot-ground reaction forces during playing. For instance, in flute playing, two forceplates, one for each foot, can serve to study the shifting effects from one foot to the other following changes in playing technique [102]. Forceplate measurements, together with kinematic and EMG measurements, may also be incorporated into a multi-segment biomechanical model for studying the biomechanics of violin playing [58].  
Other force and pressure measurements include chin force in violin players, as above-described in Section 2.2.2.  
Finger-Fingerboard Force  
A custom-designed force transducer has been used to monitor the force exerted on the fingerboard of the instrument by the left finger in playing a musical note at diverse playing tempi or other playing conditions [129; 130]. Force exertion usually comprises two distinct time-stages: (a) pressing the string to overcome its tension until contact with the fingerboard is achieved; (b) increasing the force during contact to stabilize the string in a position corresponding to the desired musical note.  
The reported results for the finger force values have ranged from 4.5 N at low tempi (less than 2 Hz) to 1.7N at high tempi (more than 2 Hz). Of all the fingers' forces, the highest is in the index finger, with a lower intensity at softer dynamic levels of the tone [129].  
The above finger force has been used as the input force in a 3D biomechanical dynamic model for the index finger, to simulate the internal tendon and joint forces of the hand. Model results using this model have yielded tendon forces around 5 N, and joint forces around 8 N [131; 132].  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Disorder Addressed** & **Methods, Variables and Analysis [Refs]** & **Musical Instrument** \\ \hline TMJ & Non-specific methods [17; 18; 19; 20; 31] & Human voice, winds, strings \\ \cline{2-3}  & Specific methods: Post-ant cephalogram and & \\  & panoramic tomograms [18; 31] & \\  & Lateral cephalogram [32] & \\  & Intra-oral device [22] & Upper strings \\  & Chin-rest [47; 48; 49; 50] & \\  & Displacement measurements [50] & \\  & FEA [51] & \\ \hline EMG (surface) [64; 65; 66]: & \\  & Average rectified [67] & \\  & Exposure variation analysis [57; 69; 70] & \\  & Signal variability [57; 67; 77; 78] & \\  & Co-contraction [35; 56; 73; 76] & \\  & Synchronicity [71; 72; 73] & \\  & Imbalance and asymmetry [67] & \\  & Risk assessment [87] & \\  & SAIS [67; 90] & \\  & Shoulder and chin rest [62; 91] & \\ Muscle Activity & Comparison with cello [56; 57; 59; 68] & Upper strings, percussion, cello \\  & Piriforms muscle syndrome [43; 93] & \\  & Fatigue [94] & \\  & Efficacy of “taping” [60] & \\  & Biofeedback [24; 95] & \\  & LBP [96; 97; 98; 99; 100] & \\  & EMG (wires) [81; 82; 83] & \\  & Possible interference with playing & \\  & H-reflex [84] & \\  & Somatosensory evoked potential [65; 85] & \\  & TMS [86] & \\ \hline \hline \end{tabular} \
\begin{tabular}{c c} \hline \hline  & Kinematics: \\  & Motion analysis [48; 101; 107], MacReflex [15], \\  & Vicon [108; 109] & Upper strings, cello, bass \\ \cline{2-3}  & Photogrammetric data with inverse dynamics & \\  & [108; 111] & \\ \hline \hline \end{tabular}
\begin{tabular}{c c} \hline \hline  & Electrogoniometers [113; 114], \\  & Potentiometers [15; 115] & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of methods, variables and analyses used for identifying and evaluating vocation-related neuro-musculoskeletal deficiencies in professional musicians (abbreviations used: TMJ = temporo mandibular joint; Post-ant = postero-anterior; EMG = electromyogram; SAIS = subacromial impingement syndrome; TMS = transcranial magnetic stimulation; LBP = low back pain).