JOURNAL WATCH Journal Watch

DOES HYPERBARIC OXYGEN EXPOSURE AFFECT HIGH-

INTENSITY, SHORT-DURATION EXERCISE PERFORMANCE? Rozenek R, Fobel BF, Banks

JC, Russo AC, Lacourse MG.

The Journal of Strength and Conditioning Research 2007;21(4):1037–1041

Hyperbaric oxygen (HBO) exposure involves the breathing of 100% oxygen under

conditions of elevated atmospheric pressure and is used to increase the oxygen content of the plasma fraction of arterial blood. The purpose of this study was to determine the effects of acute HBO exposure on selected physiological responses and performance in response to maximal lower extremity or upper extremity short-term, high-intensity exercise. The study was performed with 2 separate experiments incorporating double-blinded and randomised protocols. In experiment 1, 9 subjects ran on a treadmill at a speed of 268 miles per minutes with a predetermined grade. In experiment 2, 9 different subjects performed a repetitive bench press exercise. Both exercise protocols were designed to induce fatigue within 1–2 minutes. Within each

included range of motion and KT-1000 arthrometer measurements compared with the contralateral knee. Standardised outcome measures were used including single assessment numeric evaluation (SANE), Lysholm and Tegner Activity Score. The mean time from injury to surgery

was 9 days in the early group and 85 days in the delayed group. The average follow-up from surgery was 366 days. Articular cartilage and meniscal injuries were comparable between the 2 groups and there were no significant differences in the postoperative assessments.

sportEX comment

Early ACL reconstructions do not appear to result in loss of motion or suboptimal clinical results as long as extension and early range of motion is emphasised in rehabilitation.

www.sportEX.net sportEX comment

The application of a prophylactic probiotic is becoming more and more poplar with elite athletes seeking to reduce the effects of illness on their training regime. This study indicates that this particular substance is effective in reducing the number of days and severity of respiratory illness.

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experiment, subjects received either a 1-hour HBO exposure inspiring 100% O2 at 202.6 kPa or a 1-hour sham exposure inspiring ambient air at 121.5 kPa before exercise. No significant differences were observed in physiological responses or performance. Unlike other methods that elevate oxygen content of the blood, acute HBO exposure appears to have no significant effect on subsequent high- intensity running or lifting performance.

sportEX comment Hyperbaric oxygen has been used

in the injury recovery process. This study suggests that in terms of performance it has little effect.

RELA

REL TIONSHIP BETWEEN CYCLING MECHANICS AND CORE STABILITY. Abt JB,

Smoliga JM et al. The Journal of Strength and Conditioning Research 2007;21(4):1300–

1304

Core stability has received considerable attention with regards to functional training in sports. Core stability provides the foundation

from which power is generated in cycling. The purpose of this study was to determine the relationship between cycling mechanics and core stability. Hip, knee, and ankle joint kinematic and pedal force data were collected on 15 competitive cyclists performing an exhaustive cycling protocol while cycling untethered on a high-speed treadmill. A core fatigue workout was performed before the second treadmill test. Total frontal plane knee motion sagittal plane knee motion, and sagittal plane ankle motion increased after the core fatigue protocol. No significant differences were demonstrated for pedaling forces. Core fatigue resulted in altered cycling mechanics that might increase the risk of injury due to greater knee joint stress. Improved core stability and endurance could promote greater alignment of the lower extremity when riding for extended durations as the core is more resistant to fatigue.

sportEX comment The importance of core stability is

being questioned in some circles. This study shows that there is life in the concept yet.

ORAL ADMINISTRATION OF THE PROBIOTIC LACTOBACILLUS FERMENTUM VRI- 003 AND MUCOSAL IMMUNITY IN ENDURANCE ATHLETES. Cox AJ, Pyne DB, Saunders PU, Fricker PA. British Journal of Sports Medicine Web Feb 2008

This study looked at the effects of a probiotic on immunity. Twenty healthy elite male distance runners over a four-month period of winter training were given either a probiotic Lactobacillus fermentum VRI 003 (PCC) or a placebo containing an inert excipient. They were measured using treadmill performance (monthly), mucosal and systemic immunity (monthly), training (daily) and illness (daily). The results showed that subjects reported less than half the number of days of respiratory symptoms during PCC treatment compared with placebo. Illness severity was also lower for episodes occurring during the PCC treatment. There were no significant differences in the mean change in salivary IgA and IgA1 levels, or in interleukin IL-4 and interleukin-12 levels, between treatments. However PCC treatment elicited a two-fold greater change in whole-blood culture interferon gamma (IFN- x) compared with placebo. There were no substantial changes in running performance measures over the study period.