Kinesiology

The purpose of this study was to determine if barbell circuit training (RTC) as a model for concurrent training is superior to high intensity interval (CTHI) or moderate intensity continuous (CTMI) cycling for changes in muscular strength, hypertrophy, and body composition. Eleven trained males were recruited and counterbalanced into three groups. Each program featured three alternating days of resistance training per week, with one of the above time-equated (30-minute) concurrent training modalities between sessions. All groups increased muscular strength (p<0.05, RTC=7.48%, CTHI=10.32%, CTMI=15.74%) with no group differences (p>0.05). Increases in upper body muscle hypertrophy were similar in RTC and CTMI (p<0.01, RTC=20.18%, CTMI=20.97%), increases in lower body muscle hypertrophy only occurred in CTMI (VM: p=0.01, 38.59%, VLP: p=0.07, 13.33%), while no hypertrophy changes were detected in CTHI (p>0.05), no group experienced changes in body composition (p>0.05). These findings suggest similar muscle performance benefits from barbell circuit or cycling concurrent training.

The purpose of this study was to determine if resistance exercise altered
peripheral BDNF concentration. Eighteen trained male subjects were split into two
groups performing varied repetition ranges. DUP-HR and DUP-LR groups trained
3x/week for 8 weeks, and were equated for total volume (repetitions X sets X intensity).
Plasma BDNF and interleukin-6 (IL-6) levels were measured prior to and immediately
following the first exercise session of weeks 1, 2, 4 and 6. Pre-exercise levels were also
assessed prior to the second and third sessions of week 1 and 6. Lastly, resting levels
were measured before and after training intervention. No group differences (p>0.05) were detected for either biomarker. An acute BDNF elevation (p=0.018) was detected only in the final week of training. IL-6 elevations were detected at all acute measurements (p<0.01). BDNF and IL-6 percentage change correlated significantly (p<0.05) in week-1. No chronic alterations were observed (p>0.05).

Periodized training programs seem to augment muscle performance (i.e.,
hypertrophy, strength and muscle endurance), however, optimal repetition ranges to
achieve these adaptations are unclear. Thus, the purpose was to compare high and low
repetition daily undulating periodization (DUP) models, with equal volume on
performance. Eleven trained, college-aged males were counterbalanced into high (DUPHR) or low (DUP-LR) repetition groups. Subjects performed the squat and bench press 3X/wk. for 8wks. Outcome measures included one-repetition maximum (1RM) bench press, squat, and total strength (TS=squat+bench press), and muscle thickness (MT). 1RM strength increased with no difference between groups. Both groups increased total chest and total body MT (p<0.05); but only DUP-HR increased thigh MT (p<0.05). Effect sizes showed meaningful differences in strength favoring DUP-LR for bench press-1.48 and TS-0.89. Our findings indicate with equal volume, there may be meaningful differences in strength that are repetition-dependent, and varying responses to MT across different muscle groups.

The aim of this research was to study the coordinative dynamics of multijoint arm movements as a function of forearm spatial orientation. Six subjects rhythmically coordinated flexion and extension of the right elbow and wrist under the following conditions: (1) forearm supine: wrist flexion/elbow flexion and vice versa; and (2) forearm prone: wrist flexion/elbow extension and vice versa. Starting in either pattern, subjects rotated the forearm in eight 20 steps, producing 15 cycles of motion at a frequency of 1.25 Hz. Switching from pattern (1) to pattern (2) and vice versa was observed at a critical spatial orientation. The critical point depended on the direction of forearm rotation, thus revealing the hysteretic nature of the switching. En route to the transition, regardless of direction of change, critical fluctuations and critical slowing down were observed in the relative phasing between the joints. Such results provide definitive evidence that relative phase is a viable order parameter, spatial orientation a relevant control parameter and loss of stability the chief mechanism leading to observed changes in coordination.

The dynamics of recruitment and suppression processes are studied in the coupled pendulum paradigm developed by Kugler and Turvey (1987). Experimentally, the main concern is whether pendulum motion in this task is purely planar. Theoretically, the main concern is whether one-dimensional phase equations developed originally by Haken, Kelso and Bunz (1985) and the symmetry breaking extension by Kelso, Delcolle and Schoner (1990), can capture the richness of the dynamics of this experimental model system. In experiment 1, subjects swung single hand-held pendulums in time with an auditory metronome whose frequency increased. Bifurcations from planar to spherical pendulum motion occurred at critical cycling frequencies. Typically, these frequencies were above the pendulum's eigenfrequency. Spectral measures showed that spherical pendulum motion was generated through the recruitment of wrist abduction and adduction. The spectral measures revealed that elbow flexion and extension was recruited as movement rate increased, presumably to stabilize pendulum motion. When recruited, both components frequency- and phase-entrained with the primary pendulum mover, wrist ulnar flexion-extension. In experiment 2, subjects swung coupled pendulums in either an in-phase or anti-phase coordinative mode as movement rate increased. Transitions between coordinative modes were not observed. Pattern stability, as defined by the variability of the phase relation between the pendulums, was not affected to any large degree by increasing movement rate. Bifurcations from planar to spherical motion emerged at critical cycling frequencies. Spectral measures demonstrated that this motion was generated by abduction and adduction of the wrist. Elbow flexion-extension motion was also recruited. The newly active components frequency- and phase-entrained with wrist ulnar flexion-extension. When the same neuromuscular components were recruited simultaneously, e.g., elbow motion in both arms, the components exhibited frequency- and phase-entrainment with the task defined pattern. The results demonstrate that recruitment processes stabilize the coordinative modes, thereby reducing the need to switch patterns. Both experiments revealed a much richer dynamics than ever observed in the coupled pendulum paradigm and question the application of one-dimensional phase equation models to the coupled pendulum paradigm.