title: The Effects of Chronic Cold Water Immersion in Elite Rugby Players

authors: Tavares, Francisco

subjects: Recovery

abstract: Purpose:
While the acute effects of cold water immersion (CWI) have been widely investigated, research analysing the effects of CWI over a chronic period in highly-trained athletes is scarce. The aim of this study was to investigate the effects of CWI during an intense three week pre-season phase in elite rugby athletes.

Methods:
Twenty-three elite male rugby union athletes were randomized to either CWI (10 min at 10 ºC, n = 10) or a passive recovery control (CON, n = 12) during three-weeks of high volume training. Athletes were exposed to either CWI or CON, after each training day (12 days in total). Running loads, conditioning and gym sessions were kept the same between groups. Measures of countermovement jump (CMJ), perceived muscle soreness and wellness were obtained twice a week, and saliva samples for determining cortisol and interleukin-6 (IL-6) were collected once per week.

Results:
Although no significant differences were observed between CWI and CON for any measure, CWI resulted in lower fatigue markers throughout the study, as demonstrated by the moderate effects on muscle soreness (d = 0.58 to 0.91) and IL-6 (d = -0.83), and the small effects (d = 0.23 to 0.38) on CMJ in comparison to CON.

Conclusions:
The results from this study demonstrate that CWI may provide some beneficial effect by reducing fatigue and soreness during an intense three week training phase in elite rugby athletes.

text: The Effects of Chronic Cold Water Immersion in Elite Rugby Players Purpose:
While the acute effects of cold water immersion (CWI) have been widely investigated, research analysing the effects of CWI over a chronic period in highly-trained athletes is scarce. The aim of this study was to investigate the effects of CWI during an intense three week pre-season phase in elite rugby athletes.

Methods:
Twenty-three elite male rugby union athletes were randomized to either CWI (10 min at 10 ºC, n = 10) or a passive recovery control (CON, n = 12) during three-weeks of high volume training. Athletes were exposed to either CWI or CON, after each training day (12 days in total). Running loads, conditioning and gym sessions were kept the same between groups. Measures of countermovement jump (CMJ), perceived muscle soreness and wellness were obtained twice a week, and saliva samples for determining cortisol and interleukin-6 (IL-6) were collected once per week.

Results:
Although no significant differences were observed between CWI and CON for any measure, CWI resulted in lower fatigue markers throughout the study, as demonstrated by the moderate effects on muscle soreness (d = 0.58 to 0.91) and IL-6 (d = -0.83), and the small effects (d = 0.23 to 0.38) on CMJ in comparison to CON.

Conclusions:
The results from this study demonstrate that CWI may provide some beneficial effect by reducing fatigue and soreness during an intense three week training phase in elite rugby athletes.

year: 2018

title: Coastal and sediment dynamics in a high-energy, rocky environment

authors: McComb, Peter

abstract: A study of the wave dynamics, hydrodynamics and sediment dynamics was conducted at an energetic open-coast site at New Plymouth, New Zealand. The location features large, shore-normal reefs of volcanic agglomerate extending from an irregular shoreline, with “black” volcanic sands intermittently overlying a rocky bed. The breakwaters of an artificial harbour (Port Taranaki) interrupt the longshore littoral transport, and dredging and offshore dumping causes “downstream” erosion along the city foreshore. The key study objectives were to investigate the local coastal dynamics, and to examine ways to mitigate the effects of the harbour on the adjacent coast. 

Two large experimental field programmes were conducted involving: i) wave, current and suspended sediment measurements, ii) side-scan sonar and hydrographic survey, iii) sediment tracing, and iv) experimental dumping of 47,000 m³ of dredged sand in a rocky nearshore zone (6-10 m depth). Sediment trap calibration experiments were also performed. 

Analysis of the measured wave data has identified wave-induced motion as a significant source of velocity error in p, u, v meters on taut-wire moorings, and wave directions resolved from the cross-spectra of pressure and velocity have frequency dependent errors due to the phase difference between the pressure and velocity data. Accordingly, the spectra of wave direction should be resolved solely from velocity data. Calibration of sediment traps against an automated water sampler has provided the first strong evidence that traps are effective in deriving the time-averaged suspended sediment concentration SSC in a wave-dominated coastal environment. Rigid cylindrical traps of high Aspect Ratio have a 75% sampling efficiency. 

Wave transformations across the complex nearshore bathymetry are dominated by seabed friction and refraction. This process was simulated using the WBEND wave refraction model, applying a constant friction coefficient for sandy beds, and a Nikuradse roughness for rocky beds. Wind vector was found to influence the spatial distribution of wave energy, with whitecapping conditions under onshore-directed winds inducing a longshore “smoothing” in the wave energy, which appears to act in opposition to wave height reinforcement from refraction. 

Sediment tracing using an artificial fluorescent material proved to be an effective method for observing the transport of littoral sediments over sandy and rocky beds, over distances of up to 5 km. The tracer exhibited a horizontal diffusivity of the order 0.1 m²s⁻¹, of which approximately 5% was expressed in the cross-shore direction. 
The time-averaged entrainment (C₀) of “black” volcanic sands under high-energy conditions may be effectively predicted using the excess non-dimensional skin friction (θ₂.₅) raised to the power of 1.5, with the mean grain size used in the sediment mobility term (Ψ) and the median grain size in the friction factor (fw). The scale of turbulent mixing (lₛ) increases linearly with elevation above the bed, with a gradient of 0.46. Suspended sediments show a systematic (and linear) reduction in mean grain size with increasing elevation above bed. 

SSCs over rocky beds are supply-limited, and inversely proportional to the distance from contiguous sandy beds. Sediments are principally transported in the suspended form, and a system of irregular shore-normal reefs does not significantly obstruct the longshore flux. Rocky beds appear to be resilient to sediment inundation and the sand/rock sediment facies have remained positionally stable over 16 years. Dumping sand in a rocky reef environment does not necessarily result in adjacent beds becoming inundated with sand. In this environment, a nearshore dump mound did not migrate as a contiguous body, but slowly dispersed as suspended sediments. 

Net sediment transport at New Plymouth is directed alongshore to the northeast, although the sediments respond to local and temporal perturbations, which give rise to reversing and circulating fluxes. Port Taranaki traps 174,000 m³ of coastal sediments per year, of which 142,000 m³ accumulates at the breakwater tip. The latter are derived from the shallow zone seaward of the breakwater wall (i.e. within ∼50 m). Sediments in depths > 6 m (i.e. > 100 m from the breakwater wall) bypass the harbour and traverse the rocky reefs toward the eastern beaches. The historical offshore dumping practice removes sediments from the nearshore littoral budget, while the orientation of the main port breakwater causes the longshore sediment flux to be directed away from the adjacent (Kawaroa) coast, further reducing the supply of littoral sediments to that region. 

A new dumping ground has been identified for the breakwater-tip sediments, which is projected to retain the dredged sediments within the nearshore littoral system, feeding sand to the central and eastern city foreshore. Sedimentation of the coast immediately adjacent to the port is not expected to result from the long-term use of this ground.

text: Coastal and sediment dynamics in a high-energy, rocky environment A study of the wave dynamics, hydrodynamics and sediment dynamics was conducted at an energetic open-coast site at New Plymouth, New Zealand. The location features large, shore-normal reefs of volcanic agglomerate extending from an irregular shoreline, with “black” volcanic sands intermittently overlying a rocky bed. The breakwaters of an artificial harbour (Port Taranaki) interrupt the longshore littoral transport, and dredging and offshore dumping causes “downstream” erosion along the city foreshore. The key study objectives were to investigate the local coastal dynamics, and to examine ways to mitigate the effects of the harbour on the adjacent coast. 

Two large experimental field programmes were conducted involving: i) wave, current and suspended sediment measurements, ii) side-scan sonar and hydrographic survey, iii) sediment tracing, and iv) experimental dumping of 47,000 m³ of dredged sand in a rocky nearshore zone (6-10 m depth). Sediment trap calibration experiments were also performed. 

Analysis of the measured wave data has identified wave-induced motion as a significant source of velocity error in p, u, v meters on taut-wire moorings, and wave directions resolved from the cross-spectra of pressure and velocity have frequency dependent errors due to the phase difference between the pressure and velocity data. Accordingly, the spectra of wave direction should be resolved solely from velocity data. Calibration of sediment traps against an automated water sampler has provided the first strong evidence that traps are effective in deriving the time-averaged suspended sediment concentration SSC in a wave-dominated coastal environment. Rigid cylindrical traps of high Aspect Ratio have a 75% sampling efficiency. 

Wave transformations across the complex nearshore bathymetry are dominated by seabed friction and refraction. This process was simulated using the WBEND wave refraction model, applying a constant friction coefficient for sandy beds, and a Nikuradse roughness for rocky beds. Wind vector was found to influence the spatial distribution of wave energy, with whitecapping conditions under onshore-directed winds inducing a longshore “smoothing” in the wave energy, which appears to act in opposition to wave height reinforcement from refraction. 

Sediment tracing using an artificial fluorescent material proved to be an effective method for observing the transport of littoral sediments over sandy and rocky beds, over distances of up to 5 km. The tracer exhibited a horizontal diffusivity of the order 0.1 m²s⁻¹, of which approximately 5% was expressed in the cross-shore direction. 
The time-averaged entrainment (C₀) of “black” volcanic sands under high-energy conditions may be effectively predicted using the excess non-dimensional skin friction (θ₂.₅) raised to the power of 1.5, with the mean grain size used in the sediment mobility term (Ψ) and the median grain size in the friction factor (fw). The scale of turbulent mixing (lₛ) increases linearly with elevation above the bed, with a gradient of 0.46. Suspended sediments show a systematic (and linear) reduction in mean grain size with increasing elevation above bed. 

SSCs over rocky beds are supply-limited, and inversely proportional to the distance from contiguous sandy beds. Sediments are principally transported in the suspended form, and a system of irregular shore-normal reefs does not significantly obstruct the longshore flux. Rocky beds appear to be resilient to sediment inundation and the sand/rock sediment facies have remained positionally stable over 16 years. Dumping sand in a rocky reef environment does not necessarily result in adjacent beds becoming inundated with sand. In this environment, a nearshore dump mound did not migrate as a contiguous body, but slowly dispersed as suspended sediments. 

Net sediment transport at New Plymouth is directed alongshore to the northeast, although the sediments respond to local and temporal perturbations, which give rise to reversing and circulating fluxes. Port Taranaki traps 174,000 m³ of coastal sediments per year, of which 142,000 m³ accumulates at the breakwater tip. The latter are derived from the shallow zone seaward of the breakwater wall (i.e. within ∼50 m). Sediments in depths > 6 m (i.e. > 100 m from the breakwater wall) bypass the harbour and traverse the rocky reefs toward the eastern beaches. The historical offshore dumping practice removes sediments from the nearshore littoral budget, while the orientation of the main port breakwater causes the longshore sediment flux to be directed away from the adjacent (Kawaroa) coast, further reducing the supply of littoral sediments to that region. 

A new dumping ground has been identified for the breakwater-tip sediments, which is projected to retain the dredged sediments within the nearshore littoral system, feeding sand to the central and eastern city foreshore. Sedimentation of the coast immediately adjacent to the port is not expected to result from the long-term use of this ground.

year: 2001

title: Rewi Mokena: youngest son of Mokena Hou

authors: Hart, Philip

abstract: The youngest child of Mokena Hou, Rewi Mokena moved from place to place when young, finally settling permanently at Te Aroha. Having received some education, he was fluent in English. Like the typical rangatira of the time, he acquired interests in several blocks of land, obtained income from these in the short term, but because of financial difficulties was brought before the court several times. 
His involvement in gold mining started in a small way in 1875. Five years later, he would assist Hone Werahiko to prospect Te Aroha – and to fend off inquisitive Pakeha. He invested in claims in all of the three areas where gold was found.
By the twentieth century, Rewi was the most important rangatira at Te Aroha, and had wider influence, assisting the King Movement to seek redress for lost land. From a young age he participated in Pakeha society, notably as a rugby player, and became a prominent Mormon. His complicated private life, including bigamy and a wife’s attempted suicide because of his adultery, did not lower his high standing in Maori society nor damage his popularity with Pakeha.

text: Rewi Mokena: youngest son of Mokena Hou The youngest child of Mokena Hou, Rewi Mokena moved from place to place when young, finally settling permanently at Te Aroha. Having received some education, he was fluent in English. Like the typical rangatira of the time, he acquired interests in several blocks of land, obtained income from these in the short term, but because of financial difficulties was brought before the court several times. 
His involvement in gold mining started in a small way in 1875. Five years later, he would assist Hone Werahiko to prospect Te Aroha – and to fend off inquisitive Pakeha. He invested in claims in all of the three areas where gold was found.
By the twentieth century, Rewi was the most important rangatira at Te Aroha, and had wider influence, assisting the King Movement to seek redress for lost land. From a young age he participated in Pakeha society, notably as a rugby player, and became a prominent Mormon. His complicated private life, including bigamy and a wife’s attempted suicide because of his adultery, did not lower his high standing in Maori society nor damage his popularity with Pakeha.

year: 2016