Introduction: Aging has been shown to diminish bone blood flow in rats and humans. The purpose of this study was to determine whether blood flow to regions of the femur perfused primarily through the principal nutrient artery (PNA) are diminished with aging and whether this putative reduction in flow is associated with impaired endothelium‐dependent vasodilation. Materials and Methods: Blood flow was measured in conscious young adult (4–6 mo old) and aged (24–26 mo old) male Fischer‐344 rats using radiolabeled microspheres. Endothelium‐dependent vasodilation of the PNA was assessed in vitro using acetylcholine (ACh), whereas the contribution of the NO synthase (NOS) and cyclooxygenase (COX) signaling pathways to endothelium‐dependent vasodilation was determined using the NOS and COX inhibitors L‐NAME and indomethacin, respectively. Results: Femoral blood flow in the aged rats was 21% and 28% lower in the proximal and distal metaphyses, respectively, and 45% lower in the diaphyseal marrow. Endothelium‐dependent vasodilation was reduced with old age (young: 83 ± 6% maximal relaxation; aged: 62 ± 5% maximal relaxation), whereas endothelium‐independent vasodilation (sodium nitroprusside) was unaffected by age. The reduction in endothelium‐dependent vasodilation was mediated through impairment of the NOS signaling pathway, which resulted in lower NO bioavailability (young: 168 ± 56 nM; aged: 50 ± 7 nM). Conclusions: These data show that reductions in metaphyseal bone and diaphyseal marrow perfusion with old age are associated with diminished endothelium‐dependent vasodilation through an impairment of the NOS mechanism. Such age‐related changes in bone perfusion and vascular NO signaling could impact clinical bone loss, increase risk of fracture, and impair fracture healing in the elderly.

Abstract available in the Medicine & Science in Sports & Exercise.

PURPOSE: The purpose of the study was to examine the relationships between muscle cross-sectional area (CSA) measured by either ultrasonography or biopsy and measures of isometric peak force (IPF) and rate of force development (RFD). METHODS: Fifteen well-trained males (IPF=4445.467 + 613.690 N) participated in the study. Prior to testing and following an overnight fast, each subject’s vastus lateralis (VL) was measured for anatomical CSA (ACSA) using ultrasonography. A muscle biopsy was also sampled from the VL of each subject immediately after the ACSA measurement and at the same site on the VL. Fiber CSA (FCSA) was assessed using immunofluorescent techniques. IPF and RFD at 0-50ms, 0-100ms, 0-150ms, and 0-200ms were assessed during an isometric mid-thigh pull test on force platforms sampling at 1000Hz. Pearson product-moment correlations were calculated between muscle sizes and performance. Statistical significance was set as p≤0.050. RESULTS: Statistically significant correlations were observed between Type II FCSA and IPF (r=0.774, p<0.001), RFD150 (r=0.661, p=0.007), and RFD200 (r=0.725, p=0.002). ACSA was only significantly associated with IPF (r=0.596, p=0.019). Type I FCSA did not relate to any performance measures. CONCLUSIONS: It is clear from our results and previous literature that ultrasonography and muscle biopsy data provide relevant information regarding muscle size and performance. However, the discrepancies observed in the current study between the two suggest each is providing slightly different information to researchers. Specifically, Type II FCSA might be superior when considering more sensitive performance measurements such as RFD.

Abstract available in the 10th Annual Coaches and Sport Science College .

Abstract available in the 9th Annual Coaches and Sport Science College.

No description available.

No description available.

Much of the current literature related to injuries in sport has addressed the influence of a particular exercise intervention on a specific type of injury without considering changes in sport performance. The purpose of this research was to investigate an interdisciplinary approach to athlete development and its initial effects on injury rates and measures of performance in collegiate baseball. In October 2008, an NCAA Division I baseball team began working with a sport performance enhancement group (SPEG) which consists of a collaborative effort between sport coaches, sport medicine and sport science departments. Injury rates were calculated for each academic year from 2006/2007 through 2010/2011. As part of the athlete monitoring program provided through SPEG, peak force was measured using an isometric mid-thigh pull from 2008/2009 through 2010/2011. Team win percentage and home runs were also reported from 2003/2004 through 2010/2011. Compared to 2006/2007 and 2007/2008, injury rates during 2008/2009 decreased 40% and 16%, 2009/2010 decreased 64% and 48%, while 2010/2011 decreased 33% and 6%. Team mean allometrically scaled isometric peak force (IPFa) increased each year from 2008/2009 through 2010/2011 (200.6 N, 229.6 N, 244.2 N). IPFa during 2009/2010 and 2010/2011 were significantly greater than 2008/2009 (p = .001 and .002). Win percentage increased from 2008/2009 through 2010/2011 (47%, 53%, 63%) and the 2010/2011 win percentage was higher than any other year since 2003/2004. Total team home runs during 2009/2010 and 2010/2011 were higher than any other season since 2003/2004. These results seem to indicate that the collaborative efforts of SPEG were able to substantially reduce injury rates while increasing lab based and on-field performance.

No description available.

No description available.