Grant Landers

Athletic induced iron deficiency: new insights into the role of inflammation, cytokines and hormones

Iron is utilised by the body for oxygen transport and energy production, and is therefore essential to athletic performance. Commonly, athletes are diagnosed as iron deficient, however, contrasting evidence exists as to the severity of deficiency and the effect on performance. Iron losses can result from a host of mechanisms during exercise such as hemolysis, hematuria, sweating and gastrointestinal bleeding. Additionally, recent research investigating the anemia of inflammation during states of chronic disease has allowed us to draw some comparisons between unhealthy populations and athletes. The acute-phase response is a well-recognised reaction to both exercise and disease. Elevated cytokine levels from such a response have been shown to increase the liver production of the hormone Hepcidin. Hepcidin up-regulation has a negative impact on the iron transport and absorption channels within the body, and may explain a potential new mechanism behind iron deficiency in athletes. This review will attempt to explore the current literature that exits in this new area of iron metabolism and exercise.

Morphology and performance of world championship triathletes

Performance is related to body morphology in many sports. With triathlon making its debut into the Olympic programme in 2000, it was deemed important to determine which physical characteristics of elite-level triathletes were significantly related to performance. Seventy-one elite and junior elite triathletes, from 11 nations, competing at the 1997 World Triathlon Championships were measured on a battery of 28 anthropometric dimensions. A factor analysis was conducted, which reduced the number of variables to four and these were used in a stepwise linear regression to determine which morphological factors were important to performance. Elite triathletes were significantly (p< 0.05) faster than their junior counterparts (males 1:52:26 vs. 2:03:23 and females 2:07:01 vs. 2:14:05) and showed less variation in performance times. Run time variation was the largest of the component disciplines and tended to show the importance of this discipline to the final outcome. Following a factor analysis the four distinguishable morphological factors that emerged were: robustness, adiposity, segmental lengths and skeletal mass. Relating these factors to the total time obtained by the triathletes in this study yielded a regression equation that correlated significantly with all triathletes, accounting for 47% of the variance in total triathlon duration. The regression equations illustrated the importance of low levels of adiposity for elite triathletes for total time and most of the subdisciplines. The other factor that showed importance was that proportionally longer segmental lengths contributed to successful swimming outcome.

Training Surface and Intensity : Inflammation, Hemolysis, and Hepcidin Expression

PURPOSE This investigation assessed the effects of training intensity and ground surface type on hemolysis, inflammation, and hepcidin activity during running. METHODS Ten highly trained male endurance athletes completed a graded exercise test, two continuous 10-km runs on a grass (GRASS) and a bitumen road surface (ROAD) at 75%-80% peak VO2 running velocity, and a 10 x 1-km interval running session (INT) at 90%-95% of the peak VO2 running velocity. Venous blood and urine samples were collected before, immediately after, and at 3 and 24 h after exercise. Serum samples were analyzed for circulating levels of IL-6, free hemoglobin (Hb), haptoglobin (Hp), iron, and ferritin. Urine samples were analyzed for changes in hepcidin expression. RESULTS After running, the IL-6 and free Hb were significantly greater, and serum Hp was significantly lower than preexercise values in all three conditions (P < 0.05). Furthermore, IL-6 levels and the change in free Hb from baseline were significantly greater in the INT compared with those in the GRASS (P < 0.05). There were no differences between the GRASS and ROAD training surfaces (P > 0.05). Serum iron and ferritin were significantly increased after exercise in all three conditions (P < 0.05) but were not different between trials. CONCLUSION Greater running intensities incur more inflammation and hemolysis, but these variables were not affected by the surface type trained upon.

Relationship between inflammatory cytokines and self-report measures of training overload

It has been purported that inflammatory cytokines may be responsible for the aetiology of overtraining. The aim of the present study was to investigate the relationship between self-reported measures of overtraining and inflammatory cytokines. Eight elite male rowers were monitored in their natural training environment for 8 weeks prior to the 2007 Rowing World Championships. During this period of intense endurance training, self-report measures of overtraining and inflammatory cytokines (Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p70, and Tumor Necrosis Factor (TNF)-α) were assessed fortnightly. Consistent with previous findings, proinflammatory cytokines IL-1β and TNF-α were significantly associated (p ≤ 0.05) with measures of depressed mood, sleep disturbances, and stress. Similarly, IL-6 was significantly associated (p ≤ 0.01) with measures of depressed mood, sleep disturbances, and fatigue. These results are consistent with previous hypotheses describing how overtraining may be caused by excessive cytokine release, and lend further support for a cytokine hypothesis of overtraining.

Effect of swimming intensity on subsequent cycling and overall triathlon performance.

Objectives: To investigate the effects of different swimming intensities on subsequent cycling and overall triathlon performance. Methods: Nine highly trained, male triathletes completed five separate laboratory sessions comprising one graded exercise test, a swim time trial (STT), and three sprint distance triathlons (TRI). The swimming velocities of the three TRI sessions were 80–85% (S80), 90–95% (S90), and 98–102% (S100) of the STT velocity. Subsequent cycling and running were performed at a perceived maximal intensity. Swimming stroke mechanics were measured during the swim. Plasma lactate concentration and ratings of perceived exertion were recorded at the conclusion of the swim and over the course of subsequent cycling and running. Oxygen consumption was recorded during the cycle. Results: The S80 and S90 cycle times were faster than the S100 cycle time (p<0.05). The overall triathlon time of S80 was faster than that of S100 (p<0.05). The S100 swim was characterised by a greater stroke rate than S80 and S90 (p<0.05) and a greater plasma lactate concentration than S80 (p<0.01). Conclusion: A swimming intensity below that of a time trial effort significantly improves subsequent cycling and overall triathlon performance.

Impact of training on changes in perceived stress and cytokine production.

Data on training of competitive athletes and the inflammatory response, and, more specifically, the utility of psychological inventories to monitor this response in regards to overreaching is limited. The aim of the present study was to investigate the association of the Perceived Stress Scale (PSS) and inflammatory markers in elite rowers. Eight rowers (males n = 4; females n = 4) were monitored over an 8-week training period, comprising 12 sessions each week and training an average 3.11 h·d−1. Training volume was periodized weekly while intensity was maintained throughout the study. Perceived stress was measured weekly pretraining, and capillary blood samples (500 μL) were taken post-training. Significant associations between perceived stress and cytokines interleukin-6 (p < .05) and tumor necrosis factor alpha (p < .05) were observed. While further investigation of the role of cytokines in the overtraining process is required, these data provide preliminary support for an association between perceived stress and the inflammatory responses to training.

An analysis of the rollover backstroke turn by age-group swimmers.

Abstract Kinetic (3‐D force plate), kinematic (videography) and temporal characteristics of backstroke turns by 20 male and 16 female swimmers were recorded to identify and describe key elements of backstroke turning performance. Data were recorded during a 50m maximum effort swim in a 25 metre pool. A Pearson product moment correlation matrix revealed that the 5 m RTT was significantly correlated with anthropometric measures of height, mass, trochanteric height and age; kinetic measures of horizontal impulse and peak force; and kinematic measures of wall contact time and peak velocity. The stepwise multiple regression equation to predict 5 m RTT was: 19.6‐0.75 trochanteric height‐1.8 wall exit velocity‐0.03 peak vertical force. Four key factors were identified from a principle components factor analysis ‐ anthropometry and force, post‐turn velocity, force preparation and rotational skills. Implications from the findings were that age‐group backstrokers should ‘hit the wall hard’ with relatively extended legs to reduce swim distance and push‐off deceleration; use minimal wall contact time, and maximise forces to develop high horizontal velocities in a streamlined position.

Effect of Warm-Up on Intermittent Sprint Performance

We aimed to investigate the effects of different warm-up (WUP) intensities on 10 min of subsequent intermittent-sprint running performance. Eleven male, team-sport players performed four trials in a randomized, cross-over design, consisting of an intermittent-sprint protocol (15 × 20-m sprints) that followed either no-WUP or one of three 10-min WUP trials that varied in intensity. Warm-up intensities were performed at either (1) half the difference between anaerobic threshold (AT) and lactate threshold (LT) [(AT-LT)/2] below the LT = WUP 1; (2) midway between LT and AT level = WUP 2; (3) [(AT-LT)/2] above AT = WUP 3. Sprint times were fastest following WUP 3, compared with all other trials, for sprints 1–9 and 14, as well as for total accumulated sprints, with these results supported by moderate to large effect size (ES; range: d = −0.50 to −1.06) and “possible” to “almost certain” benefits. Warm-up 3 resulted in faster intermittent-sprint running performance compared with lower intensity WUPs and no WUP for the first 6 min of sprinting, with accumulated sprints for the entire 10 min protocol also being faster after WUP 3. This information may be pertinent to coaches of team-sport games with respect to player substitutions.

Iron Regulation in Athletes: Exploring the Menstrual Cycle and Effects of Different Exercise Modalities on Hepcidin Production

The trace element iron plays a number of crucial physiological roles within the body. Despite its importance, iron deficiency remains a common problem among athletes. As an individuals iron stores become depleted, it can affect their well-being and athletic capacity. Recently, altered iron metabolism in athletes has been attributed to postexercise increases in the iron regulatory hormone hepcidin, which has been reported to be upregulated by exercise-induced increases in the inflammatory cytokine interleukin-6. As such, when hepcidin levels are elevated, iron absorption and recycling may be compromised. To date, however, most studies have explored the acute postexercise hepcidin response, with limited research seeking to minimize/attenuate these increases. This review summarizes the current knowledge regarding the postexercise hepcidin response under a variety of exercise scenarios and highlights potential areas for future research-such as: a) the use of hormones though the female oral contraceptive pill to manipulate the postexercise hepcidin response, b) comparing the use of different exercise modes (e.g., cycling vs. running) on hepcidin regulation.

Kinanthropometric differences between 1997 World championship junior elite and 2011 national junior elite triathletes

OBJECTIVES In 1997, anthropometry measures were made to determine the body size and shapes of both senior and junior elite triathletes. Since then, the junior event distance has changed and the optimal morphology of participants may have evolved. Thus the objective of this study was to compare the morphology of 1997 World championship junior elite triathlon competitors with junior elite competitors in 2011. DESIGN Comparative study of junior elite triathlete kinanthropometry. METHODS Twenty-nine males and 20 females junior elite competitors in the 1997 Triathlon World Championships underwent 26 anthropometric measurements. Results were compared with 28 male and 14 female junior elite triathletes who competed in the 2011 Australian National Junior Series, as qualifying for 2011 Triathlon World Championships. Comparisons were made on the raw scores, as well as somatotype, and body proportional scores. RESULTS Both male and female junior elite triathletes in the 2011 group were significantly more ectomorphic than their 1997 counterparts. The 2011 triathletes were also proportionally lighter, with significantly smaller flexed arm and thigh girths, and femur breadths. The 2011 males recorded significantly longer segmental lengths and lower endomorphy values than the 1997 junior males. CONCLUSIONS Junior elite triathlete morphology has evolved during the past 14 years possibly as a result of changing race distance and race tactics, highlighting the importance of continually monitoring and updating such anthropometric data.