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“In the Box”: “Spicy” heat? It is no sweat for Sporting Kansas City

Urine specific gravity, sweat patches, beet juice and more keep intensity high.

MLS: Austin FC at Sporting Kansas City Jay Biggerstaff-USA TODAY Sports

“It is spicy out here,” my girlfriend exclaimed with some delight after we exited the chilled 74° inside my place. I had just finished some Kung Pao chicken (“George likes his chicken spicy.”), and I was feeling the heat in more ways than one.

(I had to, right, Seinfeld fans? Here’s the context if you aren’t familiar.)

For the last two weeks, temperatures in Kansas City and across the Western country have risen to the upper 80s to low 90s to now upper 90s in Kansas City, a dramatic rise from a comfortable spring. Last Saturday at Children’s Mercy Park when Sporting Kansas City hosted Austin FC in an afternoon tilt, the 22 on the field basked in 86° heat. Some may not have welcomed the spice:

  • For every degree the body’s internal temperature rises, the heart beats about 10 beats per minute faster, a dramatic increase of stress (How Hot Weather Can Affect Your Heart When You Exercise – Health Essentials from Cleveland Clinic).
  • “The distance that is covered in games [by Sporting KC players] is going to be 10-20% lower [in high heat]” (Joey Harty, Sporting Kansas City, Director, Sports Performance and Science).
  • [One’s heart] may circulate two to four times as much blood each minute as it does on a cool day.
  • “In the summer, you can see guys losing 4-5% body weight just in one session, in an hour-and-a-half, just from sweating.”
  • Complex cognitive tasks such as working memory (spatial span test, pattern recognition) have been observed to be significantly impaired because of heat stress (The Impacts of Extreme Heat on Mental Health (

There are plenty of reasons why “[Major League Soccer] mandates the use of cooling breaks if the Wet Bulb Globe Temperature (WBGT) measures 82 degrees Fahrenheit or higher. Additionally, the referee can, at any time, implement a discretionary “drinks break” during cases in which player safety is determined to be at risk.” And why the only others allowed on the field, besides the players, during these 90-180 second breaks are medical personnel.

But what is WBGT (there is an app for that… WeatherFX)? The WBGT “[takes] into account the ambient temperature, humidity, wind speed, sun angle, and cloud cover at the site of the athletic activity” (Three Deadly Myths About Athletes And Heat Stress (

Okay. Those are some facts on the impact of heat – a factor that many often mention but rarely grasp the enormity of – and some background. But what does the fear factor of heat mean for how Sporting Kansas City trains and how they prepare their players?

“Usually it takes two or three weeks to acclimatize to altitude or the climate,” said Joey Harty, the director of sports performance and science for Sporting Kansas City in a phone interview with The Blue Testament on Tuesday of this week.

However, for Sporting, acclimatization has been in vogue since preseason in Arizona, in other words, acclimatization is easier for the very fit. So there is no wearing of extra clothes during training and no heat baths or sitting in a sauna after training for the boys in blue. Overall, preparation for intense heat and humidity is recognizing what causes the most outward of signs – muscle cramping (remember the heart is a muscle too) – and mitigating those factors.

High Fidelity

As one’s body works “overtime” to cool itself, the heart increases its efforts to radiate heat through the blood flowing in your veins and arteries, you sweat more, “which results in more body weight loss every training session, which then results in potential dehydration… and a lessening of muscle endurance…, which then results in cramping,” explained Harty.

“Our goal is to try and get them to maintain and be able to play at the level [the players need to].”

For example, as Sporting KC Manager Peter Vermes, Harty, and the rest of the staff build training in preparation for game day, they may orchestrate a session that includes small-sided matches like 8v8 or 7v7.

“We need to think about how we are structuring those games to be played at the right intensities,” said Harty. “Maybe instead of playing less games for more time, maybe three sets of 10 minutes, maybe we switch to four sets of six [to eight] minutes. Then the guys are able to keep playing at the same intensities for the same or longer total duration, but just broken up into more bouts.”

Even though the distance covered by a player in a match played in high heat will be “10-20% lower”, the manipulation of training variables to hit the target intensity allows players to continue to perform “high intensity actions” such as sprints and physical confrontations during a match.

Gross Anatomy

It’s a matter of personal taste, I guess… So in those physical confrontations, like in the box battling for a corner kick, would you rather tussle with a heavy sweater or a salty sweater? Either way, it is natural, kinda nasty, but natural.

At the beginning of each season, Sporting does a sweat patch analysis to see which guys sweat which way. People with white streaks on their face… those are the salty sweaters.

“Some guys sweat a lot more salt, so we always give our guys individualized electrolyte supplements pre-game and at halftime… And we are measuring them every single day,” Harty revealed. “If it is really hot, and it is after training and our dietician (Diane Robison) is noticing a trend or maybe it is one or two guys – the guys you know are heavy sweaters – then we are telling them what they need to drink post-training.”

Related, of course, is the fact that Sporting measures each player’s body weight before and after every training session, and, assumedly, every match. The threshold is not losing more than 3% body weight, yet, in the summer sometimes a player can lose 4-5% of body weight in just an hour-and-a-half session.

“The final check for making sure players are going into a game well hydrated is the urine analysis test,” Harty intimated.

Two days before a match, a Urine Specific Gravity (USG) analysis is done.

“Our dietician measures the concentration of the urine to determine the solubility of it, the level of sodium in the urine, to be able to give recommendations for what they need to be drinking”

“Are they overhydrated, meaning they need to add sodium to their diet, are they dehydrated where they need water and sodium, or are they right in that sweet spot where they to maintain the recommendations we give them?”

The rating system brings out the players’ competitiveness. Green is good, yellow is ok, red is bad. “The guys can take pride in not being bad, take ownership of it.”

Like trying to ingrain any good habit, consistency is key in training athletes.

“We [talk hydration] the whole year, so that when it comes to the summertime, when it’s really important, it is not something new that you are teaching the players; it is already a part of what they are doing. You can just emphasize it.”

Cool Runnings

Sporting has had all week to recover from Saturday’s 1-1 draw in the 86° heat as they do not play again until this Saturday at Portland Timbers. To be able to hit the necessary intensities in training and to be able to implement the match strategies (which can be somewhat dictated by the weather) to get a result in Portland, players need to recover quickly.

“If you aren’t educating them the right way, if you aren’t focusing on nutrition throughout the whole year, if you aren’t focusing on supplementation (beet juice can help with red blood cells, the transporting of oxygen in your body, thus prolonging endurance, btw… drink up!), if you aren’t focusing on hydration, your body is going to take longer to recover because you are more dehydrated, you have to expend more energy,” Harty emphasized, but there is more. “[We also] implement cooling strategies during the sessions, more importantly, during the games having the guys wear cooling vests or ice towels to assist their body in cooling down so they are expending less energy, expending less calories.”

War Games

We all know stress. And we all know too much can lead to various breakdowns in our all-too-human bodies and psyches. Nothing can ruin a moment in a match, or a whole match for a side, like an ill-advised yellow card foul at the edge of a team’s own box or a match-turning red card as a result of stress overload. And significant cerebral processing despite the stressful heat is necessary to take advantage of space and that “now” moment.

“From a mental standpoint… I think about how we periodize training and the season and how we prepare [including game strategy], we are managing stress. That is the biggest thing,” declared Harty. “Whenever we – the players, the medical staff, the performance staff, and the coaching staff – plan our season, we are looking at traveling across time zones, altitude, playing games [in high heat] like we just did and understanding that is an additional stress.

You can put together a specific protocol for recovering from heat or altitude, but, realistically, it comes down to the individual: seeing if a guy is a little out of his norm heartrate, questionnaires we ask the guys regarding soreness, sleep, fatigue, how they record they are feeling, did they lose more body weight than they typically would, did they have a higher score post-game or pre-game regarding hydration. You are just trying to make sure that guy is in a good place for the next game.”

Sporting will fly through two time zones and play at a time later than usual in Portland. However, the forecast for the Saturday evening kickoff is for a wonderful 77°. Even though the match will be played on the turf at Providence Park, the feel will be different for the players, especially since temperatures in Kansas City were forecast to reach 100° Thursday and Friday.

“Now we are going into Portland, and it is going to be a great climate,” said Harty. “I was joking with some of the players that it is going to feel like they have a third lung after training in this heat.”

(Portland… beets… I can’t resist this either… “It’s beets!”):