Search

The concept of peaking ensures that athletes have trained to attain their absolute peak performance levels prior to a competition. This study investigates the effects of peaking on the functions of neutrophils and lymphocytes in university soccer players during a five-day soccer training camp followed by two weeks of tapering. The study subjects were 22 soccer players who were members of a university soccer club. We carried out our investigation during a five-day training camp and two weeks after the training camp (i.e. the tapering period). We measured body composition, immune-related parameters (leukocyte count, neutrophil count, lymphocyte count, immunoglobulins and complements), myogenic enzymes, superoxide dismutase activity (SOD) and neutrophil functions [reactive oxygen species (ROS) production, phagocytic activity, serum opsonic activity and lymphocyte subtypes]. Leukocyte and neutrophil counts tend to increase after the training camp compared with values before the training camp, and recovered during the conditioning period, although the final values were still lower than those before the training camp. The amount of ROS production per neutrophil and level of SOD decreased significantly during the conditioning period compared with before the training camp (p < 0.05, p < 0.01, respectively). Levels of Th1 cells decreased significantly during the conditioning period compared with the training camp (p < 0.05). In conclusion, the period of two weeks for the tapering period was considered insufficient to allow the athletes' immune function to recover completely after an intensive training camp., (Copyright © 2013 John Wiley & Sons, Ltd.)

We assessed the association of neutrophil function with glycated hemoglobin (HbA1c) levels in a Japanese general population. Participants were 809 males and females who were over 20 years old living in the Iwaki region in Aomori Prefecture located in northern Japan. Lifestyle parameters (smoking, alcohol consumption, and exercise habits), HbA1c and neutrophil function such as reactive oxygen species (ROS) production capability and phagocytic activity (PA) were measured. ROS production capability was measured before and after phagocytic stimulus to obtain basal ROS production and stimulated ROS production. Level of HbA1c had a positive correlation with basal ROS production (p=0.053), a negative correlation with stimulated ROS production (p=0.072) and PA (p=0.059) only in post-menopausal groups, and not in pre-menopausal groups. However, there were no correlations between levels of HbA1c and neutrophil functions in male. In conclusion, in the present study, despite the presence of diabetes, chronic hyperglycemia was found to cause an increase in daily basal ROS production of neutrophils, and increased susceptibility to infection caused by reduced neutrophilic reaction in females in their menopause. Therefore, from the oxidative point of view, strict glycemic control is necessary to prevent post-menopausal females from developing diabetic complications in spite of the presence of diabetes., (Copyright © 2013 John Wiley & Sons, Ltd.)

In this study, changes in physical fatigue and biological functions of Japanese female soccer players were investigated by determining changes in neutrophil and lymphocyte functions. Study subjects included 18 female soccer players. Body composition, serum myogenic enzymes, neutrophil function, including reactive oxygen species (ROS) production capability, phagocytic activity (PA) and serum opsonic activity, as well as lymphocyte subpopulation were measured before and after a soccer match. Levels of myogenic enzymes (AST, ALT, CK and LDH) and immunoglobulins (IgG and IgA) and complements (C3) increased significantly after the match. In addition, leukocyte, neutrophils and lymphocyte counts increased whereas total PA decreased significantly. The number of T and Th1 cells (subsets of T helper cells) decreased whereas Th2 increased significantly. In addition, the number of B cells increased and NK cells decreased significantly after the match. The match was found to result in degenerative changes in and damage to athlete muscle tissues together with damage- and change-mediated stress. These data also suggest a post-match accelerated inflammatory reaction and potential immunosuppression as indicated by reductions in neutrophil PA and lymphocyte functions., (Copyright © 2012 John Wiley & Sons, Ltd.)

We examined changes in neutrophil function of soccer players over a 10-month period and determined its effectiveness as an index for athlete physical condition. Subjects included 21 male professional Japanese soccer players. Data on body composition, myogenic enzymes and neutrophil function were obtained before and after 2 h of training at 3 investigation points: one week before opening season, at season mid-point, and one week before the last game of the season. As a result, change ratios of myogenic enzyme levels before and after the 2-hr training session at the third investigation point were significantly higher compared to the two other points. Reactive oxygen species production and phagocytic activity significantly increased after 2-hr training session at point 1, although the extent of the increase became smaller over time and ROS production capability decreased significantly by point 3 assessment. Fatigue, especially muscle fatigue, chronically accumulated along with a gradual decrease in neutrophil immune function over the 10-month season. Therefore, determination of neutrophil function can be used as a useful index to assess and understand an athlete's physical condition., (Copyright © 2012 John Wiley & Sons, Ltd.)

We investigated the effects of dehydration after a judo practice session on player muscle and immune functions. Subjects included 25 female university judoists. Investigations were performed before and after 2.5 h of regular judo practice. Body composition, serum enzymes (myogenic enzymes, immunoglobulins and complements), neutrophils counts, reactive oxygen species (ROS) production capability, and phagocytic activity (PA) were measured. Subjects were divided into two groups according to level of dehydration after practice (mild dehydration and severe dehydration groups) and results were compared. Creatine kinase was found to increase significantly after practice. In addition, neutrophil count also increased significantly after practice in both groups. The changing ratios of IgA, IgG and C3 observed in the mild dehydration group were significantly higher than those in the severe dehydration group. In the severe dehydration group, post-practice PA/neutrophil had decreased significantly. Significant positive correlations were found between severity of dehydration and changing ratios of IgA, IgG, IgM, C3, C4 and ROS production capabilities, whereas no significant association was seen with PA and/or serum SOD activity. These results suggest that dehydration resulted in immunosuppression, including decreased neutrophil function., (Copyright © 2012 John Wiley & Sons, Ltd.)

We studied the effects of a high intensity and high frequency 3-month training program on muscle damage and neutrophil function in male judoists. The study included 15 male judoists who started intensive judo training program after a 6-month break. Creatine kinase (CK), neutrophil counts and reactive oxygen species (ROS) production capability as well as phagocytic activity (PA) of neutrophils were measured at 2 stages; entering university (pre-training) and after 3-month training (post-training). At both points, we investigated parameters three times: just before, immediately after and 24 h after a 2-h practice session. Practice-mediated change in CK was lower at post-training than at pre-training. Neutrophil count significantly increased after 2-h practice but recovered 24 h later whereas it showed no subsequent and further increased at 24 h post-practice. Although neutrophil ROS production capability and PA both decreased (breakdown) after practice session, ROS production capability increased and PA decreased (well-adapted) at the post-training. Long-term training strengthened muscular function and improved neutrophil reaction against practice-mediated stress., (Copyright © 2012 John Wiley & Sons, Ltd.)

We have evaluated the relationship between exhaled carbon monoxide (CO) level and neutrophil-related functions such as reactive oxygen species (ROS) production capability, phagocytic activity and serum opsonic activity in the general population. Serum opsonic activity was determined by measuring the effects of serum on neutrophil ROS production capability using lucigenin- and luminol-dependent chemiluminescence (LgCL, LmCL). LgCL is associated with the detection of O(2)(-) , whereas LmCL mainly detects H(2)O(2) and HOCl, which are higher reactive oxygen radicals. In females, exhaled CO level was found to have positive associations with ROS production capability and LgCL. However, the opposite tendency was seen between exhaled CO level and LmCL in both genders. This result suggests that neutrophil ROS production in females may have contributed to oxidative stress, which led to the increases in intrinsic CO and exhaled CO consequently. Such changes then may have inhibited the process of changing reactive oxygen radicals into higher oxidizing potential levels., (Copyright © 2010 John Wiley & Sons, Ltd.)