Muscle fatigue, defined as the decline in skeletal muscle force or power during sustained activity, is a complex, multifactorial phenomenon critical to physical performance. While myoelectric manifestations are well studied, simultaneous hemodynamic assessment is emerging. Unlike near-infrared spectroscopy (NIRS), this study employs photoacoustic imaging (PAI), combining laser illumination and ultrasound detection for enhanced depth sensitivity. Simultaneous high-density surface electromyography (HD-sEMG) and multispectral PAI were performed using a Verasonics Vantage 256 system with an Opotek Phocus Mobile SE laser and a 128-element linear ultrasound transducer, acquiring 10 wavelengths per acquisition. HD-sEMG was recorded via a 32-channel electrode matrix over the forearm. Two healthy subjects completed two to four trials of rest and sustained isometric contraction (little finger, right hand, until exhaustion), yielding a preliminary multimodal dataset.