To date, biomechanical analyses of soccer kicking have focused predominantly on lower-extremity motions, with little emphasis on the trunk and upper body. The purpose of this study was to evaluate differences in trunk axial kinematics between novice (n = 10) and skilled (n = 10) participants, as well as to establish the relationship of trunk axial motion and sagittal plane thigh rotation to poststrike ball velocity. Three-dimensional body segmental motion data were captured using high-resolution motion analysis (120 Hz) while each participant completed 5 maximal instep soccer-style kicks. The results demonstrate that skilled participants use 53% greater axial trunk range of motion compared with novice participants (P < .01), as well as 62% greater peak trunk rotation velocity (P < .01). The results also show a moderate, positive correlation of peak trunk rotation velocity with poststrike ball velocity (r = .57; P < .01), and peak hip flexion velocity with poststrike ball velocity (r = .63; P < .01). The current study highlights the potential for trunk rotation-specific training to improve maximum instep kick velocity in developing soccer athletes.
Adam M. Fullenkamp, Brian M. Campbell, C. Matthew Laurent and Amanda Paige Lane
Adam M. Fullenkamp, Danilo V. Tolusso, C. Matthew Laurent, Brian M. Campbell and Andrea E. Cripps
Context: Motorized treadmills (MTs) present an altered motor task compared to overground (OG) locomotion in that MT belt surfaces are motor-driven, whereas individuals walking/running OG must propel themselves. A possible solution may lie with novel nonmotorized treadmill (NMT) devices as the belt surface is propelled by the user. Objective: The purpose of this study was to compare gait performance during both MT and NMT locomotion to OG. Design: Crossover study. Setting: A university research laboratory. Patients: A total of 20 healthy adults (10 women) participated in the study. Intervention: Each participant performed self-selected walking and running OG, and on both an MT and NMT. Main Outcome Measure: Shoulder, trunk, and lower-extremity kinematics were analyzed for each treadmill condition and compared to OG. Results: The analyses demonstrated that there were no differences between MT and OG gait kinematics during either walking or running. However, NMT gait showed increased hip, knee, and ankle flexions in late swing and early stance compared to OG during both walking and running. For example, during walking, the NMT elicited hip-, knee-, and ankle-flexion/extension angles of 34.7°, 8.0°, and 3.6° at foot strike compared to 24.8°, −3.1°, and −5.8° in the OG condition (P < .05). There was also a significant reduction in trunk-flexion/extension range of motion during running compared to OG (7.7° in NMT vs 9.8° in OG). Conclusions: These differences may have implications for both training and rehabilitation on an NMT. Future studies should consider the influence of NMT familiarization on gait performance and should emphasize the assessment of neuromuscular performance.
W. Steven Tucker, Charles W. Armstrong, Erik E. Swartz, Brian M. Campbell and James M. Rankin
Closed kinetic chain exercises are reported to provide a more functional rehabilitation outcome.
To determine the amount of muscle activity in 4 shoulder muscles during exercise on the Cuff Link.
10 men and 10 women, age 18–50.
Subjects performed 3 sets of 5 revolutions on the Cuff Link in non-weight-bearing, partial-weight-bearing, and full-weight-bearing positions.
Main Outcome Measures:
Electromyography data were collected from the upper trapezius, anterior deltoid, serratus anterior, and pectoralis major and were expressed as percentage of maximal isometric contractions.
Significant differences were found across the weight-bearing conditions for all 4 muscles. Exercise on the Cuff Link required minimal to significant amounts of muscle recruitment.
Muscle recruitment increases as weight bearing increases during use of the Cuff Link, suggesting an increase in dynamic stabilization of the glenohumeral joint.