Quantifying Activity of the Erector Spinae Longissimus Subgroup Using EMG During Prolonged Driving

Prolonged driving has been associated with localized muscle fatigue, particularly in the lumbar region, posing safety and ergonomic concerns. This study investigates the dynamics of multivariate surface electromyography (sEMG) features to detect fatigue during extended driving sessions. EMG signals were recorded from the erector spinae muscles of seven subjects across two backrest inclination angles (100°, 110°) during real-world, multi-hour driving tasks. Spectrogram-based features, including mean frequency (MNF), median frequency (MDF), and root-mean-square (RMS), were extracted using a sliding-window method for analysis. Co-temporal trends in these features were analyzed to identify fatigue regions, marked by simultaneous decreases in MNF and MDF and/or increases in RMS. Paired t-tests were used to compare the two backrest inclination angles across subjects for each fatigue duration and fatigue event count. Results demonstrate that seat inclination angle significantly affects fatigue duration and number of events, with the 100° angle leading to notably more fatigue than 110° (p<0.01). This work could contribute a framework for time-resolved, EMG fatigue modeling in realistic driving scenarios. ABSTRAK: Pemanduan terlalu lama dikaitkan dengan keletihan otot setempat, khususnya di bahagian lumbar, menimbulkan kebimbangan dari segi keselamatan dan ergonomik. Kajian ini mengkaji dinamika ciri permukaan multivarian elektromiografi (sEMG) bagi mengesan keletihan semasa sesi pemanduan jauh. Isyarat EMG direkodkan daripada otot erektor spina dari 7 subjek pada dua sudut kecondongan penyandar (100°, 110°) semasa aktiviti pemanduan sebenar berlangsung selama beberapa jam. Ciri berasaskan spektrogram, termasuk frekuensi purata (MNF), frekuensi median (MDF) dan purata punca kuasa dua (RMS) telah diekstrak menggunakan tetingkap-gelongsor. Corak serentak dalam ciri-ciri ini dianalisa bagi mengenal pasti kawasan keletihan, dibuktikan dengan penurunan MNF dan MDF serta/atau peningkatan RMS. Ujian-t berkembar digunakan bagi membandingkan dua sudut kecondongan penyandar merentas subjek bagi setiap tempoh keletihan dan bilangan kejadian. Dapatan kajian menunjukkan bahawa sudut kecondongan penyandar memberi kesan signifikan terhadap tempoh keletihan dan bilangan kejadian, dengan sudut 100° menghasilkan lebih banyak keletihan berbanding 110° (p<0.01). Kajian ini berpotensi menyumbang kepada satu rangka kerja pada model keletihan EMG beresolusi masa dalam senario pemanduan realistik.