Graduation Year
2024
Document Type
Open Access Senior Thesis
Degree Name
Bachelor of Arts
Department
Biology
Reader 1
Jenna Monroy
Reader 2
Marion Preest
Terms of Use & License Information
Rights Information
2024 Jemma F Bosselman
Abstract
Identification of knee motor control strategy is salient both for biomechanical understanding of the lower limb and for medical applications. Integral to knee function are the quadriceps and hamstring, an antagonistic muscle pair. Sub-optimal relative activation of the pair can increase injury potential. Muscle activation patterns are largely activity specific, necessitating muscle control research across various tasks. Single leg hopping has been sparsely studied, particularly for muscle activation in relation to hopping frequency. This project thus aimed to determine the effect of single leg hopping frequency on quadriceps and hamstring activation using surface electromyography (EMG), with the vastus lateralis (VL) and biceps femoris (BF) as representative muscles respectively. EMG and motion capture data were collected from 5 subjects at hopping frequencies of 1.5 Hz, 2.2 Hz, 3 Hz, and their natural frequency. Maximum activation, integrals of activation peaks, and timing of peaks and maxima were collected and normalized. VL activation maxima decreased as hopping frequency increased (p < 0.05), with BF maxima instead increasing at 3 Hz (p < 0.05). Integrals decreased overall with increasing hopping frequency for both the VL and BF (p < 0.05). The VL had higher maxima at low and natural frequencies compared to the BF, while the BF had greater maxima at medium and high frequencies (p < 0.05). Both the VL and BF activated before foot-ground contact times (p < 0.05), and both were active during the majority of the hop. The VL activation onset and maximum times occurred earlier than for the BF (p < 0.05), and VL activation timing shifted earlier as hopping frequency increased (p < 0.05). Results suggest that quadriceps and hamstring activation decrease as hopping frequency increases, but that the hamstring is more active in comparison to the quadriceps at higher frequencies. The quadriceps and hamstring also seemed to be largely coactive during continuous single leg hopping.
Recommended Citation
Bosselman, Jemma, "Hamstring and Quadriceps Activation During Single Leg Hopping at Varying Frequencies: Electromyography Analysis" (2024). Scripps Senior Theses. 2538.
https://scholarship.claremont.edu/scripps_theses/2538
