Influence of Postexercise Cooling on Muscle Oxygenation and Blood Volume Changes
In the May 2013 issue of Medicine & Science in Sports & Exercise ®, the authors sought to investigate the effects of postexercise cold water immersion (CWI) on tissue oxygenation and blood volume changes following intense exercise (1). The theory behind the use of CWI in exercise recovery is proposed to be associated with the rapid reduction in core temperature, which is thought to minimize fatigue as well as suppress muscle blood flow and metabolic activity.
The study looked at nine physically active men with an average age of 23.8 who had no lower body injuries and had rested from activity for 48 h. The subjects performed 30 min of continuous running (CR) at 70% of their predetermined maximal treadmill velocity (V max), which was followed by 10 bouts of intermittent running (INT) at V max. Once the exercise was completed, one of the participants’ legs was immersed in a cold water bath (CWI, 10°C) for 15 min. The other leg remained outside the cold water bath in order to serve as the control (CON). The investigators used a single-leg design to control for the influence of central cardiovascular changes on local muscle perfusion and thus to provide insight into the effects of changes in muscle temperature per se on hemodynamic changes.
The vastus lateralis (VL) skin temperature (Tskvl), VL oxygenation (tissue oxygenation index (TOI)), and blood volume changes (total hemoglobin volume (tHb)) were monitored continuously throughout all exercise and CWI using near-infrared spectroscopy.
The results demonstrated no significant difference in Tskvl, TOI, or tHb between CON and CWI during CR or INT. However Tskvl was significantly lower in CWI when compared to CON throughout immersion. There also were significant peak differences that occurred at the end of immersion with CON = 35.1°C ± 0.6°C versus CWI = 16.9°C ± 1.7°C. tHb was significantly lower during CWI compared with CON at most time points with the peak differences of 20% ± 4% at the end of the 15 min of immersion. In addition, TOI was significantly higher in CWI when compared with CON. Here peak differences of 2.5% ± 1% were evident at the 12th minute of immersion.
Based on these findings, the authors concluded that postexercise cooling decreased microvascular perfusion and muscle metabolic activity, which is consistent with the proposed mechanisms by which CWI is hypothesized to improve targeted muscle recovery.
Bottom Line: The major findings of this study were that muscle perfusion, as evidenced by the rise in postexercise tHb concentration, was attenuated with 15 min of CWI and TOI was increased during the 15 min of CWI, indicating reduced muscle metabolic activity — both of which support CWI as a means to improve local muscle recovery through reduction in exercise-induced muscle edema.
Knee Biomechanics during a Jump-Cut Maneuver: Effects of Gender and Anterior Cruciate Ligament Surgery
The May 2013 issue of Medicine & Science in Sports & Exercise ® includes a study that compares kinetic and knee kinematic measurements from male and female anterior cruciate ligament (ACL)-intact (ACLINT) and ACL-reconstructed (ACLREC) subjects during a jump-cut maneuver using biplanar videoradiography (2). The authors studied 10 ACLINT (five men and five women) and 10 ACLREC (four men and six women, five years postsurgery) subjects. Each subject performed a jump-cut maneuver by landing on a single leg and performing a 45° side-step cut. A force plate measured ground reaction forces (GRF), which were expressed relative to the subject’s body weight. A biplanar videoradiography system and an optical motion capture system were used to determine six-degree-of-freedom knee kinematics.
The results were significant for female ACLINT subjects landing with a larger peak vertical GRF compared to male ACLINT subjects. ACLINT subjects landed with a significantly larger peak GRF compared to ACLREC subjects. Irrespective of ACL reconstruction status, female subjects demonstrated less knee flexion angle excursion and had an increased average rate of anterior tibial translation after contact compared to male subjects. In addition, ACLREC subjects had a lower rate of anterior tibial translation compared to ACLINT subjects. There were no other striking differences observed in other knee motion parameters.
The authors proposed two major findings of the study. First was that women who have never had an ACL reconstruction appeared to perform the jump-cut maneuver with a smaller amount of knee flexion angle excursion as well as a larger peak vertical GRF when compared to men with or without prior ACL surgery and other women with a history of ACL reconstruction. This resulted in an increased rate of anterior tibial translation for these female subjects. Secondly both the male and female ACLREC subjects performed the jump-cut maneuver with less energy than ACLINT subjects resulting in a lower peak vertical GRF even 5 years or more after their reconstruction. This finding was hypothesized to be the result of differences in strength, confidence, habit, and/or training following their injury.
Bottom Line: This study demonstrates measurable differences in knee kinematic measurements and force plate kinetic data in female subjects with no history of ACL reconstruction when compared to both ACL intact male subjects and either men or women with a history of ACL reconstruction. This supports the hypothesis that there are kinematic differences between men and women with regard to landing maneuvers that contribute to noncontact ACL injuries.
1. Ihsan M, Watson G, Lipski M, Abbiss CR. Influence of post exercise cooling on muscle oxygenation and blood volume changes. Med. Sci. Sports Exerc. 2013; 45: 876–82.
2. Miranda DL, Fodale PD, Hulstyn MJ, et al. Knee biomechanics during a jump–cut maneuver: effects of gender & ACL surgery. Med. Sci. Sports Exerc. 2013; 45: 942–51.