Comparison of Division II College Offensive and Defensive Football Players’ Upper Body Strength Across One Repetition Maximum Test and The NFL‐225 Test

The purpose of this study was to evaluate the effectiveness of predicting actual one repetition maximum (1RM) bench press strength from the National Football League (NFL) 225-test in college football players. Forty-one Division II college football players participated in this study. Participants’ upper body strength scores were expressed relative to body weight and results were compared across both tests. Mayhew et al. equation was used to predict 1RM. A repeated measures ANOVA and one-way ANOVA was used to compare the groups. The present study found that the Mayhew equation overestimated relative upper body strength of college football players, while high degree of reliability was found between the actual 1RM and the NFL-225 tests [Wilks λ =0.43, F (1,40) = 53.07, p =0.000, Eta-squared =0.57] and the correlation between these two tests was very high (r =0.94, p\u3c0.001). The present study also found that defensive players were stronger than offensive players when scores were expressed relative to body weight. The finding of this study indicates that the NFL-225 test’s applicability may not be identical for all college players. This study elucidates some of the difficulties associated with predicting 1RM. However, while it is difficult to predict 1RM, testing using sub-maximal loads are far less time consuming especially when they involve a large number of athletes. The results of this study should facilitate coaches in choosing the most appropriate strength testing procedure for their programs

Stable Isotope Biogeochemistry of Seabird Guano Fertilization: Results from Growth Chamber Studies with Maize (Zea Mays)

Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration) in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (δ(15)N). Animal excrement is known to impact plant δ(15)N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint.This paper presents isotopic (δ(13)C and δ(15)N) and vital data for maize (Zea mays) fertilized with Peruvian seabird guano under controlled conditions. The level of (15)N enrichment in fertilized plants is very large, with δ(15)N values ranging between 25.5 and 44.7‰ depending on the tissue and amount of fertilizer applied; comparatively, control plant δ(15)N values ranged between -0.3 and 5.7‰. Intraplant and temporal variability in δ(15)N values were large, particularly for the guano-fertilized plants, which can be attributed to changes in the availability of guano-derived N over time, and the reliance of stored vs. absorbed N. Plant δ(13)C values were not significantly impacted by guano fertilization. High concentrations of seabird guano inhibited maize germination and maize growth. Moreover, high levels of seabird guano greatly impacted the N metabolism of the plants, resulting in significantly higher tissue N content, particularly in the stalk.The results presented in this study demonstrate the very large impact of seabird guano on maize δ(15)N values. The use of seabird guano as a fertilizer can thus be traced using stable isotope analysis in food chemistry applications (certification of organic inputs). Furthermore, the fertilization of maize with seabird guano creates an isotopic signature very similar to a high-trophic level marine resource, which must be considered when interpreting isotopic data from archaeological material